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Kwon Y, Singh S, Rodriguez D, Chau AL, Pitenis AA, De Tomaso AW, Valentine MT. Mechanical resilience of the sessile tunicate Botryllus schlosseri. J Exp Biol 2023; 226:jeb245124. [PMID: 37929758 PMCID: PMC10753489 DOI: 10.1242/jeb.245124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 10/23/2023] [Indexed: 11/07/2023]
Abstract
We demonstrate that the sessile tunicate Botryllus schlosseri is remarkably resilient to applied loads by attaching the animals to an extensile substrate subjected to quasistatic equiradial loads. Animals can withstand radial extension of the substrate to strain values as high as 20% before they spontaneously detach. In the small to moderate strain regime, we found no relationship between the dynamic size of the external vascular bed and the magnitude of applied stretch, despite known force sensitivities of the vascular tissue at the cellular level. We attribute this resilience to the presence and mechanical properties of the tunic, the cellulose-enriched gel-like substance that encases the animal bodies and surrounding vasculature.
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Affiliation(s)
- Younghoon Kwon
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93117, USA
| | - Shambhavi Singh
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93117, USA
| | - Delany Rodriguez
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93117, USA
| | - Allison L. Chau
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93117, USA
| | - Angela A. Pitenis
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93117, USA
| | - Anthony W. De Tomaso
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93117, USA
| | - Megan T. Valentine
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93117, USA
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Mitchell NP, Cislo DJ. TubULAR: tracking in toto deformations of dynamic tissues via constrained maps. Nat Methods 2023; 20:1980-1988. [PMID: 38057529 PMCID: PMC10848277 DOI: 10.1038/s41592-023-02081-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 10/10/2023] [Indexed: 12/08/2023]
Abstract
A common motif in biology is the arrangement of cells into tubes, which further transform into complex shapes. Traditionally, analysis of dynamic tissues has relied on inspecting static snapshots, live imaging of cross-sections or tracking isolated cells in three dimensions. However, capturing the interplay between in-plane and out-of-plane behaviors requires following the full surface as it deforms and integrating cell-scale motions into collective, tissue-scale deformations. Here, we present an analysis framework that builds in toto maps of tissue deformations by following tissue parcels in a static material frame of reference. Our approach then relates in-plane and out-of-plane behaviors and decomposes complex deformation maps into elementary contributions. The tube-like surface Lagrangian analysis resource (TubULAR) provides an open-source implementation accessible either as a standalone toolkit or as an extension of the ImSAnE package used in the developmental biology community. We demonstrate our approach by analyzing shape change in the embryonic Drosophila midgut and beating zebrafish heart. The method naturally generalizes to in vitro and synthetic systems and provides ready access to the mechanical mechanisms relating genetic patterning to organ shape change.
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Affiliation(s)
- Noah P Mitchell
- Kavli Institute for Theoretical Physics, University of California Santa Barbara, Santa Barbara, CA, USA.
- Department of Physics, University of California Santa Barbara, Santa Barbara, CA, USA.
| | - Dillon J Cislo
- Department of Physics, University of California Santa Barbara, Santa Barbara, CA, USA.
- Center for Studies in Physics and Biology, The Rockefeller University, New York, NY, USA.
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Rodriguez D, Taketa DA, Madhu R, Kassmer S, Loerke D, Valentine MT, Tomaso AWD. Vascular Aging in the Invertebrate Chordate, Botryllus schlosseri. Front Mol Biosci 2021; 8:626827. [PMID: 33898513 PMCID: PMC8060491 DOI: 10.3389/fmolb.2021.626827] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/03/2021] [Indexed: 12/13/2022] Open
Abstract
Vascular diseases affect over 1 billion people worldwide and are highly prevalent among the elderly, due to a progressive deterioration of the structure of vascular cells. Most of our understanding of these age-related cellular changes comes from in vitro studies on human cell lines. Further studies of the mechanisms underlying vascular aging in vivo are needed to provide insight into the pathobiology of age-associated vascular diseases, but are difficult to carry out on vertebrate model organisms. We are studying the effects of aging on the vasculature of the invertebrate chordate, Botryllus schlosseri. This extracorporeal vascular network of Botryllus is transparent and particularly amenable to imaging and manipulation. Here we use a combination of transcriptomics, immunostaining and live-imaging, as well as in vivo pharmacological treatments and regeneration assays to show that morphological, transcriptional, and functional age-associated changes within vascular cells are key hallmarks of aging in B. schlosseri, and occur independent of genotype. We show that age-associated changes in the cytoskeleton and the extracellular matrix reshape vascular cells into a flattened and elongated form and there are major changes in the structure of the basement membrane over time. The vessels narrow, reducing blood flow, and become less responsive to stimuli inducing vascular regression. The extracorporeal vasculature is highly regenerative following injury, and while age does not affect the regeneration potential, newly regenerated vascular cells maintain the same aged phenotype, suggesting that aging of the vasculature is a result of heritable epigenetic changes.
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Affiliation(s)
- Delany Rodriguez
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Daryl A. Taketa
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Roopa Madhu
- Department of Physics and Astronomy, University of Denver, Denver, CO, United States
| | - Susannah Kassmer
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Dinah Loerke
- Department of Physics and Astronomy, University of Denver, Denver, CO, United States
| | - Megan T. Valentine
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Anthony W. De Tomaso
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
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