1
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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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Peskin B, Norman J, Bagwell J, Lin A, Adhyapok P, Di Talia S, Bagnat M. Dynamic BMP signaling mediates notochord segmentation in zebrafish. Curr Biol 2023:S0960-9822(23)00671-1. [PMID: 37285843 DOI: 10.1016/j.cub.2023.05.039] [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: 01/31/2023] [Revised: 04/12/2023] [Accepted: 05/16/2023] [Indexed: 06/09/2023]
Abstract
The vertebrate spine is a metameric structure composed of alternating vertebral bodies (centra) and intervertebral discs.1 Recent studies in zebrafish have shown that the epithelial sheath surrounding the notochord differentiates into alternating cartilage-like (col2a1/col9a2+) and mineralizing (entpd5a+) segments which serve as a blueprint for centra formation.2,3,4,5 This process also defines the trajectories of migrating sclerotomal cells that form the mature vertebral bodies.4 Previous work demonstrated that notochord segmentation is typically sequential and involves the segmented activation of Notch signaling.2 However, it is unclear how Notch is activated in an alternating and sequential fashion. Furthermore, the molecular components that define segment size, regulate segment growth, and produce sharp segment boundaries have not been identified. In this study, we uncover that a BMP signaling wave acts upstream of Notch during zebrafish notochord segmentation. Using genetically encoded reporters of BMP activity and signaling pathway components, we show that BMP signaling is dynamic as axial patterning progresses, leading to the sequential formation of mineralizing domains in the notochord sheath. Genetic manipulations reveal that type I BMP receptor activation is sufficient to ectopically trigger Notch signaling. Moreover, loss of Bmpr1ba and Bmpr1aa or Bmp3 function disrupts ordered segment formation and growth, which is recapitulated by notochord-specific overexpression of the BMP antagonist, Noggin3. Our data suggest that BMP signaling in the notochord sheath precedes Notch activation and instructs segment growth, facilitating proper spine morphogenesis.
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Affiliation(s)
- Brianna Peskin
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - James Norman
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jennifer Bagwell
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Adam Lin
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Priyom Adhyapok
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Stefano Di Talia
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA; Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Michel Bagnat
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA.
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3
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Zhou KC, Harfouche M, Cooke CL, Park J, Konda PC, Kreiss L, Kim K, Jönsson J, Doman T, Reamey P, Saliu V, Cook CB, Zheng M, Bechtel JP, Bègue A, McCarroll M, Bagwell J, Horstmeyer G, Bagnat M, Horstmeyer R. Parallelized computational 3D video microscopy of freely moving organisms at multiple gigapixels per second. Nat Photonics 2023; 17:442-450. [PMID: 37808252 PMCID: PMC10552607 DOI: 10.1038/s41566-023-01171-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 02/03/2023] [Indexed: 10/10/2023]
Abstract
Wide field of view microscopy that can resolve 3D information at high speed and spatial resolution is highly desirable for studying the behaviour of freely moving model organisms. However, it is challenging to design an optical instrument that optimises all these properties simultaneously. Existing techniques typically require the acquisition of sequential image snapshots to observe large areas or measure 3D information, thus compromising on speed and throughput. Here, we present 3D-RAPID, a computational microscope based on a synchronized array of 54 cameras that can capture high-speed 3D topographic videos over an area of 135 cm2, achieving up to 230 frames per second at spatiotemporal throughputs exceeding 5 gigapixels per second. 3D-RAPID employs a 3D reconstruction algorithm that, for each synchronized snapshot, fuses all 54 images into a composite that includes a co-registered 3D height map. The self-supervised 3D reconstruction algorithm trains a neural network to map raw photometric images to 3D topography using stereo overlap redundancy and ray-propagation physics as the only supervision mechanism. The resulting reconstruction process is thus robust to generalization errors and scales to arbitrarily long videos from arbitrarily sized camera arrays. We demonstrate the broad applicability of 3D-RAPID with collections of several freely behaving organisms, including ants, fruit flies, and zebrafish larvae.
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Affiliation(s)
- Kevin C. Zhou
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
- Ramona Optics Inc., 1000 W Main St., Durham, NC 27701, USA
- Current affiliation: Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
| | - Mark Harfouche
- Ramona Optics Inc., 1000 W Main St., Durham, NC 27701, USA
| | - Colin L. Cooke
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
| | - Jaehee Park
- Ramona Optics Inc., 1000 W Main St., Durham, NC 27701, USA
| | - Pavan C. Konda
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Lucas Kreiss
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Kanghyun Kim
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Joakim Jönsson
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Thomas Doman
- Ramona Optics Inc., 1000 W Main St., Durham, NC 27701, USA
| | - Paul Reamey
- Ramona Optics Inc., 1000 W Main St., Durham, NC 27701, USA
| | - Veton Saliu
- Ramona Optics Inc., 1000 W Main St., Durham, NC 27701, USA
| | - Clare B. Cook
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
- Ramona Optics Inc., 1000 W Main St., Durham, NC 27701, USA
| | - Maxwell Zheng
- Ramona Optics Inc., 1000 W Main St., Durham, NC 27701, USA
| | | | - Aurélien Bègue
- Ramona Optics Inc., 1000 W Main St., Durham, NC 27701, USA
| | - Matthew McCarroll
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Jennifer Bagwell
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | | | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Roarke Horstmeyer
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
- Ramona Optics Inc., 1000 W Main St., Durham, NC 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
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4
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Wopat S, Adhyapok P, Daga B, Crawford JM, Peskin B, Norman J, Bagwell J, Fogerson SM, Di Talia S, Kiehart DP, Charbonneau P, Bagnat M. Axial segmentation by iterative mechanical signaling. bioRxiv 2023:2023.03.27.534101. [PMID: 37034817 PMCID: PMC10081202 DOI: 10.1101/2023.03.27.534101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
In bony fishes, formation of the vertebral column, or spine, is guided by a metameric blueprint established in the epithelial sheath of the notochord. Generation of the notochord template begins days after somitogenesis and even occurs in the absence of somite segmentation. However, patterning defects in the somites lead to imprecise notochord segmentation, suggesting these processes are linked. Here, we reveal that spatial coordination between the notochord and the axial musculature is necessary to ensure segmentation of the zebrafish spine both in time and space. We find that the connective tissues that anchor the axial skeletal musculature, known as the myosepta in zebrafish, transmit spatial patterning cues necessary to initiate notochord segment formation, a critical pre-patterning step in spine morphogenesis. When an irregular pattern of muscle segments and myosepta interact with the notochord sheath, segments form non-sequentially, initiate at atypical locations, and eventually display altered morphology later in development. We determine that locations of myoseptum-notochord connections are hubs for mechanical signal transmission, which are characterized by localized sites of deformation of the extracellular matrix (ECM) layer encasing the notochord. The notochord sheath responds to the external mechanical changes by locally augmenting focal adhesion machinery to define the initiation site for segmentation. Using a coarse-grained mathematical model that captures the spatial patterns of myoseptum-notochord interactions, we find that a fixed-length scale of external cues is critical for driving sequential segment patterning in the notochord. Together, this work identifies a robust segmentation mechanism that hinges upon mechanical coupling of adjacent tissues to control patterning dynamics.
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Affiliation(s)
- Susan Wopat
- Department of Cell Biology, Duke University, Durham, North Carolina 27710, USA
- Present address: Department of Physics, University of California Santa Barbara, Santa Barbara, California 93106, USA
- Authors contributed equally to this work
| | - Priyom Adhyapok
- Department of Cell Biology, Duke University, Durham, North Carolina 27710, USA
- Authors contributed equally to this work
| | - Bijoy Daga
- Department of Cell Biology, Duke University, Durham, North Carolina 27710, USA
- Present address: Institute of Medical Sciences, Foresterhill Health Campus, University of Aberdeen, Aberdeen AB25 2ZD, UK
- Authors contributed equally to this work
| | - Janice M. Crawford
- Department of Biology, Duke University, Durham, North Carolina 27710, USA
| | - Brianna Peskin
- Department of Cell Biology, Duke University, Durham, North Carolina 27710, USA
| | - James Norman
- Department of Cell Biology, Duke University, Durham, North Carolina 27710, USA
| | - Jennifer Bagwell
- Department of Cell Biology, Duke University, Durham, North Carolina 27710, USA
| | | | - Stefano Di Talia
- Department of Cell Biology, Duke University, Durham, North Carolina 27710, USA
| | - Daniel P. Kiehart
- Department of Biology, Duke University, Durham, North Carolina 27710, USA
| | - Patrick Charbonneau
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, North Carolina 27710, USA
- Lead contact
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5
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Zhou KC, Harfouche M, Cooke CL, Park J, Konda PC, Kreiss L, Kim K, Jönsson J, Doman J, Reamey P, Saliu V, Cook CB, Zheng M, Bechtel JP, Bègue A, McCarroll M, Bagwell J, Horstmeyer G, Bagnat M, Horstmeyer R. Parallelized computational 3D video microscopy of freely moving organisms at multiple gigapixels per second. ArXiv 2023:arXiv:2301.08351v1. [PMID: 36713250 PMCID: PMC9882581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To study the behavior of freely moving model organisms such as zebrafish (Danio rerio) and fruit flies (Drosophila) across multiple spatial scales, it would be ideal to use a light microscope that can resolve 3D information over a wide field of view (FOV) at high speed and high spatial resolution. However, it is challenging to design an optical instrument to achieve all of these properties simultaneously. Existing techniques for large-FOV microscopic imaging and for 3D image measurement typically require many sequential image snapshots, thus compromising speed and throughput. Here, we present 3D-RAPID, a computational microscope based on a synchronized array of 54 cameras that can capture high-speed 3D topographic videos over a 135-cm^2 area, achieving up to 230 frames per second at throughputs exceeding 5 gigapixels (GPs) per second. 3D-RAPID features a 3D reconstruction algorithm that, for each synchronized temporal snapshot, simultaneously fuses all 54 images seamlessly into a globally-consistent composite that includes a coregistered 3D height map. The self-supervised 3D reconstruction algorithm itself trains a spatiotemporally-compressed convolutional neural network (CNN) that maps raw photometric images to 3D topography, using stereo overlap redundancy and ray-propagation physics as the only supervision mechanism. As a result, our end-to-end 3D reconstruction algorithm is robust to generalization errors and scales to arbitrarily long videos from arbitrarily sized camera arrays. The scalable hardware and software design of 3D-RAPID addresses a longstanding problem in the field of behavioral imaging, enabling parallelized 3D observation of large collections of freely moving organisms at high spatiotemporal throughputs, which we demonstrate in ants (Pogonomyrmex barbatus), fruit flies, and zebrafish larvae.
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6
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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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7
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Lieb A, Garner Q, Reynolds N, Bagwell J, Grindstaff T. The Effect Of Verbal Cues On Lower Extremity Kinetics During Running. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000686436.19117.60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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8
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Bagwell J, Norman J, Ellis K, Peskin B, Hwang J, Ge X, Nguyen SV, McMenamin SK, Stainier DY, Bagnat M. Notochord vacuoles absorb compressive bone growth during zebrafish spine formation. eLife 2020; 9:51221. [PMID: 31995030 PMCID: PMC7012607 DOI: 10.7554/elife.51221] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [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: 08/20/2019] [Accepted: 01/28/2020] [Indexed: 12/27/2022] Open
Abstract
The vertebral column or spine assembles around the notochord rod which contains a core made of large vacuolated cells. Each vacuolated cell possesses a single fluid-filled vacuole, and loss or fragmentation of these vacuoles in zebrafish leads to spine kinking. Here, we identified a mutation in the kinase gene dstyk that causes fragmentation of notochord vacuoles and a severe congenital scoliosis-like phenotype in zebrafish. Live imaging revealed that Dstyk regulates fusion of membranes with the vacuole. We find that localized disruption of notochord vacuoles causes vertebral malformation and curving of the spine axis at those sites. Accordingly, in dstyk mutants the spine curves increasingly over time as vertebral bone formation compresses the notochord asymmetrically, causing vertebral malformations and kinking of the axis. Together, our data show that notochord vacuoles function as a hydrostatic scaffold that guides symmetrical growth of vertebrae and spine formation.
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Affiliation(s)
- Jennifer Bagwell
- Department of Cell Biology, Duke University, Durham, United States
| | - James Norman
- Department of Cell Biology, Duke University, Durham, United States
| | - Kathryn Ellis
- Department of Cell Biology, Duke University, Durham, United States
| | - Brianna Peskin
- Department of Cell Biology, Duke University, Durham, United States
| | - James Hwang
- Department of Cell Biology, Duke University, Durham, United States
| | - Xiaoyan Ge
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, United States
| | - Stacy V Nguyen
- Biology Department, Boston College, Boston, United States
| | | | - Didier Yr Stainier
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, United States.,Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, United States
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9
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Ye L, Mueller O, Bagwell J, Bagnat M, Liddle RA, Rawls JF. High fat diet induces microbiota-dependent silencing of enteroendocrine cells. eLife 2019; 8:48479. [PMID: 31793875 PMCID: PMC6937151 DOI: 10.7554/elife.48479] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [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: 05/15/2019] [Accepted: 11/26/2019] [Indexed: 12/18/2022] Open
Abstract
Enteroendocrine cells (EECs) are specialized sensory cells in the intestinal epithelium that sense and transduce nutrient information. Consumption of dietary fat contributes to metabolic disorders, but EEC adaptations to high fat feeding were unknown. Here, we established a new experimental system to directly investigate EEC activity in vivo using a zebrafish reporter of EEC calcium signaling. Our results reveal that high fat feeding alters EEC morphology and converts them into a nutrient insensitive state that is coupled to endoplasmic reticulum (ER) stress. We called this novel adaptation 'EEC silencing'. Gnotobiotic studies revealed that germ-free zebrafish are resistant to high fat diet induced EEC silencing. High fat feeding altered gut microbiota composition including enrichment of Acinetobacter bacteria, and we identified an Acinetobacter strain sufficient to induce EEC silencing. These results establish a new mechanism by which dietary fat and gut microbiota modulate EEC nutrient sensing and signaling.
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Affiliation(s)
- Lihua Ye
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, United States.,Division of Gastroenterology, Department of Medicine, Duke University School of Medicine, Durham, United States
| | - Olaf Mueller
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, United States
| | - Jennifer Bagwell
- Department of Cell Biology, Duke University School of Medicine, Durham, United States
| | - Michel Bagnat
- Department of Cell Biology, Duke University School of Medicine, Durham, United States
| | - Rodger A Liddle
- Division of Gastroenterology, Department of Medicine, Duke University School of Medicine, Durham, United States
| | - John F Rawls
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, United States.,Division of Gastroenterology, Department of Medicine, Duke University School of Medicine, Durham, United States
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10
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Wopat S, Bagwell J, Sumigray KD, Dickson AL, Huitema LFA, Poss KD, Schulte-Merker S, Bagnat M. Spine Patterning Is Guided by Segmentation of the Notochord Sheath. Cell Rep 2019; 22:2026-2038. [PMID: 29466731 PMCID: PMC5860813 DOI: 10.1016/j.celrep.2018.01.084] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [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: 10/07/2017] [Revised: 01/10/2018] [Accepted: 01/26/2018] [Indexed: 01/05/2023] Open
Abstract
The spine is a segmented axial structure made of alternating vertebral bodies (centra) and intervertebral discs (IVDs) assembled around the notochord. Here, we show that, prior to centra formation, the outer epithelial cell layer of the zebrafish notochord, the sheath, segments into alternating domains corresponding to the prospective centra and IVD areas. This process occurs sequentially in an anteroposterior direction via the activation of Notch signaling in alternating segments of the sheath, which transition from cartilaginous to mineralizing domains. Subsequently, osteoblasts are recruited to the mineralized domains of the notochord sheath to form mature centra. Tissue-specific manipulation of Notch signaling in sheath cells produces notochord segmentation defects that are mirrored in the spine. Together, our findings demonstrate that notochord sheath segmentation provides a template for vertebral patterning in the zebrafish spine.
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Affiliation(s)
- Susan Wopat
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Jennifer Bagwell
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Kaelyn D Sumigray
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Dermatology, Duke University Medical Center, Durham, NC 27710, USA
| | - Amy L Dickson
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Regeneration Next, Duke University, Durham, NC 27710, USA
| | - Leonie F A Huitema
- Hubrecht Institute - KNAW & UMC Utrecht, 3584 CT, Utrecht, the Netherlands
| | - Kenneth D Poss
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Regeneration Next, Duke University, Durham, NC 27710, USA
| | - Stefan Schulte-Merker
- Hubrecht Institute - KNAW & UMC Utrecht, 3584 CT, Utrecht, the Netherlands; Institute for Cardiovascular Organogenesis and Regeneration, Faculty of Medicine, WWU Münster, 48149 Münster, Germany; CiM Cluster of Excellence (EXC1003-CiM), 48149 Münster, Germany
| | - Michel Bagnat
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Regeneration Next, Duke University, Durham, NC 27710, USA.
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11
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Norman J, Sorrell EL, Hu Y, Siripurapu V, Garcia J, Bagwell J, Charbonneau P, Lubkin SR, Bagnat M. Tissue self-organization underlies morphogenesis of the notochord. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2017.0320. [PMID: 30249771 DOI: 10.1098/rstb.2017.0320] [Citation(s) in RCA: 13] [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] [Accepted: 08/03/2018] [Indexed: 12/13/2022] Open
Abstract
The notochord is a conserved axial structure that in vertebrates serves as a hydrostatic scaffold for embryonic axis elongation and, later on, for proper spine assembly. It consists of a core of large fluid-filled vacuolated cells surrounded by an epithelial sheath that is encased in extracellular matrix. During morphogenesis, the vacuolated cells inflate their vacuole and arrange in a stereotypical staircase pattern. We investigated the origin of this pattern and found that it can be achieved purely by simple physical principles. We are able to model the arrangement of vacuolated cells within the zebrafish notochord using a physical model composed of silicone tubes and water-absorbing polymer beads. The biological structure and the physical model can be accurately described by the theory developed for the packing of spheres and foams in cylinders. Our experiments with physical models and numerical simulations generated several predictions on key features of notochord organization that we documented and tested experimentally in zebrafish. Altogether, our data reveal that the organization of the vertebrate notochord is governed by the density of the osmotically swelling vacuolated cells and the aspect ratio of the notochord rod. We therefore conclude that self-organization underlies morphogenesis of the vertebrate notochord.This article is part of the Theo Murphy meeting issue on 'Mechanics of development'.
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Affiliation(s)
- James Norman
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Emma L Sorrell
- Department of Cell Biology, Duke University, Durham, NC 27710, USA.,Department of Mathematics, North Carolina State University, Raleigh, NC 27695-8205, USA
| | - Yi Hu
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Vaishnavi Siripurapu
- Department of Cell Biology, Duke University, Durham, NC 27710, USA.,North Carolina School of Science and Mathematics, Durham, NC 27705, USA
| | - Jamie Garcia
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Jennifer Bagwell
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | | | - Sharon R Lubkin
- Department of Mathematics, North Carolina State University, Raleigh, NC 27695-8205, USA
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
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12
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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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Lathan C, Myler A, Bagwell J, Powers CM, Fisher BE. Pressure-controlled treadmill training in chronic stroke: a case study with AlterG. J Neurol Phys Ther 2015; 39:127-33. [PMID: 25742371 DOI: 10.1097/npt.0000000000000083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND PURPOSE Body-weight-supported treadmill training has been shown to be an effective intervention to improve walking characteristics for individuals who have experienced a stroke. A pressure-controlled treadmill utilizes a sealed chamber in which air pressure can be altered in a controlled manner to counteract the effects of gravity. The focus of this case study was to assess the immediate and short-term impact of a pressure-controlled treadmill to improve gait parameters, reduce fall risk, improve participation, and reduce the self-perceived negative impact of stroke in an individual with chronic stroke. CASE DESCRIPTION The subject was an 81-year-old man (14.5 months poststroke). He had slow walking speed, poor endurance, and multiple gait deviations. INTERVENTION The subject trained 4 times per week for 4 weeks (40 minutes per session) on a pressure-controlled treadmill (AlterG M320) to counter the influence of gravity on the lower extremities. OUTCOMES Following training, self-selected gait speed increased from 0.50 m/s to 0.96 m/s, as measured by the 10-meter walk test. Stride length increased from 0.58 m to 0.95 m after training and to 1.00 m at 1-month follow-up. Peak hip flexion increased from 3.7° to 24.6° after training and to 19.4° at 1-month follow-up. Peak knee flexion increased from 19.4° to 34.3° after training and to 42.7° at 1-month follow-up. Measures of endurance, fall risk, and percentage of perceived recovery also were found to improve posttraining. DISCUSSION Training with a pressure-controlled treadmill may be a viable alternative to traditional body-weight-supported treadmill training for persons poststroke. Additional studies with larger sample sizes are needed to elucidate the role of pressure-controlled treadmill training in this population. Video abstract available for more insights from the authors (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A97).
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Affiliation(s)
- Cherise Lathan
- Clinical Faculty and Clinical Physical Therapy (CL), Keck Medical Center of USC, Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles; Rancho Los Amigos National Rehabilitation Center (AM), Downey, California; Musculoskeletal Biomechanics Research Laboratory (JB), University of Southern California, Los Angeles; Biokinesiology and Musculoskeletal Biomechanics Research Lab (CMP), Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles; and Clinical Physical Therapy and Neuroplasticity and Imaging Laboratory (BEF), Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles
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14
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Khayambashi K, Fallah A, Movahedi A, Bagwell J, Powers C. Posterolateral hip muscle strengthening versus quadriceps strengthening for patellofemoral pain: a comparative control trial. Arch Phys Med Rehabil 2014; 95:900-7. [PMID: 24440362 DOI: 10.1016/j.apmr.2013.12.022] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [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: 07/21/2013] [Revised: 12/13/2013] [Accepted: 12/28/2013] [Indexed: 01/11/2023]
Abstract
OBJECTIVE To compare the efficacy of posterolateral hip muscle strengthening versus quadriceps strengthening in reducing pain and improving health status in persons with patellofemoral pain (PFP). DESIGN Comparative control trial. SETTING Rehabilitation facility. PARTICIPANTS Persons with a diagnosis of PFP (N=36; 18 men, 18 women). INTERVENTIONS Patients were alternately assigned to a posterolateral hip muscle strengthening group (9 men and 9 women) or a quadriceps strengthening group (9 men and 9 women). The posterolateral hip muscle strengthening group performed hip abductor and external rotator strengthening exercises, whereas the quadriceps strengthening group performed quadriceps strengthening exercises (3 times a week for 8wk). MAIN OUTCOME MEASURES Pain (visual analog scale [VAS]) and health status (Western Ontario McMaster Universities Osteoarthritis Index [WOMAC]) were assessed at baseline, postintervention, and 6-month follow-up. RESULTS Significant improvements in VAS and WOMAC scores were observed in both groups from baseline to postintervention and baseline to 6-month follow-up (P<.001). Improvements in VAS and WOMAC scores in the posterolateral hip exercise group were superior to those in the quadriceps exercise group postintervention and at 6-month follow-up (P<.05). CONCLUSIONS Although both intervention programs resulted in decreased pain and improved function in persons with PFP, outcomes in the posterolateral hip exercise group were superior to the quadriceps exercise group. The superior outcomes obtained in the posterolateral hip exercise group were maintained 6 months postintervention.
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Affiliation(s)
| | - Alireza Fallah
- College of Sport Sciences, University of Isfahan, Isfahan, Iran
| | | | - Jennifer Bagwell
- Jacquelin Perry Musculoskeletal Biomechanics Research Laboratory, Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA
| | - Christopher Powers
- Jacquelin Perry Musculoskeletal Biomechanics Research Laboratory, Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA.
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15
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Ryan S, Willer J, Marjoram L, Bagwell J, Mankiewicz J, Leshchiner I, Goessling W, Bagnat M, Katsanis N. Rapid identification of kidney cyst mutations by whole exome sequencing in zebrafish. Development 2013; 140:4445-51. [PMID: 24130329 DOI: 10.1242/dev.101170] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Forward genetic approaches in zebrafish have provided invaluable information about developmental processes. However, the relative difficulty of mapping and isolating mutations has limited the number of new genetic screens. Recent improvements in the annotation of the zebrafish genome coupled to a reduction in sequencing costs prompted the development of whole genome and RNA sequencing approaches for gene discovery. Here we describe a whole exome sequencing (WES) approach that allows rapid and cost-effective identification of mutations. We used our WES methodology to isolate four mutations that cause kidney cysts; we identified novel alleles in two ciliary genes as well as two novel mutants. The WES approach described here does not require specialized infrastructure or training and is therefore widely accessible. This methodology should thus help facilitate genetic screens and expedite the identification of mutants that can inform basic biological processes and the causality of genetic disorders in humans.
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Affiliation(s)
- Sean Ryan
- Department of Cell Biology, Duke University, 333 B, Nanaline Duke Building, Durham, NC 27710, USA
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16
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Abstract
The zebrafish notochord vacuole, which has long been known to be important for vertebrate development but poorly classified at a cell biological level, is identified as a specialized lysosome-related organelle that is necessary both early, for embryonic axis elongation, and late, for spine morphogenesis. The notochord plays critical structural and signaling roles during vertebrate development. At the center of the vertebrate notochord is a large fluid-filled organelle, the notochord vacuole. Although these highly conserved intracellular structures have been described for decades, little is known about the molecular mechanisms involved in their biogenesis and maintenance. Here we show that zebrafish notochord vacuoles are specialized lysosome-related organelles whose formation and maintenance requires late endosomal trafficking regulated by the vacuole-specific Rab32a and H+-ATPase–dependent acidification. We establish that notochord vacuoles are required for body axis elongation during embryonic development and identify a novel role in spine morphogenesis. Thus, the vertebrate notochord plays important structural roles beyond early development.
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Affiliation(s)
- Kathryn Ellis
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
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17
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Bautista AP, D'Souza NB, Lang CH, Bagwell J, Spitzer JJ. Alcohol-induced downregulation of superoxide anion release by hepatic phagocytes in endotoxemic rats. Am J Physiol 1991; 260:R969-76. [PMID: 1852129 DOI: 10.1152/ajpregu.1991.260.5.r969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bacterial endotoxins [lipopolysaccharide (LPS)] are potent immunomodulators, and ethanol is known to depress certain immune defense mechanisms. Thus the combined impact of these two agents on the generation of superoxide anion (O2(-).) by isolated hepatic phagocytic cells was investigated. Ethanol was infused intravenously into rats for 7 h, and Escherichia coli LPS was injected intravenously at 4 h after ethanol administration. Control groups received an equal volume of saline or ethanol alone. Nonparenchymal cells that were composed of endothelial and Kupffer cells and few polymorphonuclear neutrophils (PMN; less than 1%) were obtained after collagenase-pronase digestion. In the LPS-treated rats, the total number of PMN per liver increased significantly. Histological sections of the liver showed PMN infiltration and areas of necrosis after LPS treatment with or without ethanol. In the presence of either phorbol 12-myristate 13-acetate or opsonized zymosan in vitro, Kupffer cells and hepatic PMN from LPS-treated rats generated large amounts of O2(-).. Ethanol intoxication in vitro by these cells to 50%. Ethanol alone (without LPS) had no effect on the production of O2(-).. These studies demonstrate that ethanol intoxication was associated with the downregulation of the LPS-enhanced in vivo priming of hepatic phagocytes to generate O2(-). in vitro and may thus contribute to the enhanced susceptibility of alcoholic subjects to develop an infection.
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Affiliation(s)
- A P Bautista
- Department of Physiology, Louisiana State University Medical Center, New Orleans 70112
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