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Fujikake Y, Fukuda K, Matsushita K, Iwatani Y, Fujimoto K, Nishino AS. Pulsation waves along the Ciona heart tube reverse by bimodal rhythms expressed by a remote pair of pacemakers. J Exp Biol 2024; 227:jeb246810. [PMID: 38682233 DOI: 10.1242/jeb.246810] [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: 10/06/2023] [Accepted: 04/11/2024] [Indexed: 05/01/2024]
Abstract
The heart of ascidians (marine invertebrate chordates) has a tubular structure, and heartbeats propagate from one end to the other. The direction of pulsation waves intermittently reverses in the heart of ascidians and their relatives; however, the underlying mechanisms remain unclear. We herein performed a series of experiments to characterize the pacemaker systems in isolated hearts and their fragments, and applied a mathematical model to examine the conditions leading to heart reversals. The isolated heart of Ciona robusta autonomously generated pulsation waves at ∼20 to 25 beats min-1 with reversals at ∼1 to 10 min intervals. Experimental bisections of isolated hearts revealed that independent pacemakers resided on each side and also that their beating frequencies periodically changed as they expressed bimodal rhythms, which comprised an ∼1.25 to 5.5 min acceleration/deceleration cycle of a beating rate of between 0 and 25 beats min-1. Only fragments including 5% or shorter terminal regions of the heart tube maintained autonomous pulsation rhythms, whereas other regions did not. Our mathematical model, based on FitzHugh-Nagumo equations applied to a one-dimensional alignment of cells, demonstrated that the difference between frequencies expressed by the two independent terminal pacemakers determined the direction of propagated waves. Changes in the statuses of terminal pacemakers between the excitatory and oscillatory modes as well as in their endogenous oscillation frequencies were sufficient to lead to heart reversals. These results suggest that the directions of pulsation waves in the Ciona heart reverse according to the changing rhythms independently expressed by remotely coupled terminal pacemakers.
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Affiliation(s)
- Yuma Fujikake
- Department of Biology, Graduate School of Agriculture and Life Science, Hirosaki University, Hirosaki 036-8561, Japan
- Department of Bioresources Science, United Graduate School of Agricultural Sciences, Iwate University, Hirosaki 036-8561, Japan
| | - Kéita Fukuda
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
| | - Katsuyoshi Matsushita
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
- Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Yasushi Iwatani
- Department of Science and Technology, Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan
- Department of Robotics, Faculty of Engineering, Kindai University, Higashi-Hiroshima 739-2116, Japan
| | - Koichi Fujimoto
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
- Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Atsuo S Nishino
- Department of Biology, Graduate School of Agriculture and Life Science, Hirosaki University, Hirosaki 036-8561, Japan
- Department of Bioresources Science, United Graduate School of Agricultural Sciences, Iwate University, Hirosaki 036-8561, Japan
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Abstract
Cardiac dyads are the site of communication between the sarcoplasmic reticulum (SR) and infoldings of the sarcolemma called transverse-tubules (TT). During heart excitation–contraction coupling, Ca2+-influx through L-type Ca2+ channels in the TT is amplified by release of Ca2+-from the SR via type 2 ryanodine receptors, activating the contractile apparatus. Key proteins involved in cardiac dyad function are bridging integrator 1 (BIN1), junctophilin 2 and caveolin 3. The work presented here aims to reconstruct the evolutionary history of the cardiac dyad, by surveying the scientific literature for ultrastructural evidence of these junctions across all animal taxa; phylogenetically reconstructing the evolutionary history of BIN1; and by comparing peptide motifs involved in TT formation by this protein across metazoans. Key findings are that cardiac dyads have been identified in mammals, arthropods and molluscs, but not in other animals. Vertebrate BIN1 does not group with members of this protein family from other taxa, suggesting that invertebrate BINs are paralogues rather orthologues of this gene. Comparisons of BIN1 peptide sequences of mammals with those of other vertebrates reveals novel features that might contribute to TT and dyad formation. The analyses presented here suggest that the cardiac dyad evolved independently several times during metazoan evolution: an unexpected observation given the diversity of heart structure and function between different animal taxa. This article is part of the theme issue ‘The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease’.
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Affiliation(s)
- John James Mackrill
- Department of Physiology, School of Medicine, University College Cork, Western Gateway Building, Western Road, Cork T12 XF62, Republic of Ireland
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The pericardium of Oikopleura dioica (Tunicata, Appendicularia) contains two distinct cell types and is rotated by 90 degrees to the left. ZOOMORPHOLOGY 2021. [DOI: 10.1007/s00435-021-00538-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractThe planktonic Oikopleura dioica belongs to Tunicata, the probable sister taxon to Craniota, and might show plesiomorphic characters, conserved from the common lineage of Tunicata and Craniota. In O. dioica a pericardium in a position similar to other chordates but also to the heart and pericardium of craniates is found. Surprisingly, little is known about the ultrastructure of the pericardium in O. dioica. Here, we show based on electron microscopy that the pericardium is completely lined by a single layer of 16 epithelial cells: 6 epithelial myocardial cells on the left side of the pericardium and 10 peritoneal cells constituting the right side. One of the peritoneal cells, situated at the ventral border between peritoneal cells and myocardial cells has an extension that anchors the pericardium to the basal lamina beneath the latero-ventral epidermis. The primary body cavity of O. dioica appears quite uniformly clear in electron microscopic aspect but several sheets, resembling the basal lamina of the pericardium cross the larger spaces of the body cavity and connect to the pericardial basal lamina. This is the first detailed description of two distinct cell types in the epithelial lining of the pericardium of O. dioica. In comparison with other chordates, we conclude that two cell types can be reconstructed for the last common ancestor of Chordata at least. The position of the pericardium at the intersection of trunk and tail in combination with the basal-lamina like sheets spanning the hemocoel is probably of importance for the function of the circulation of the hemocoelic fluid. Similar to the tail, the axis of the pericardium is shifted through 90 degrees to the left as compared to the main body axis of the trunk and we infer that this shift is an apomorphic character of Appendicularia.
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Johnson CJ, Razy-Krajka F, Stolfi A. Expression of smooth muscle-like effectors and core cardiomyocyte regulators in the contractile papillae of Ciona. EvoDevo 2020; 11:15. [PMID: 32774829 PMCID: PMC7397655 DOI: 10.1186/s13227-020-00162-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/22/2020] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The evolution of vertebrate smooth muscles is obscured by lack of identifiable smooth muscle-like cells in tunicates, the invertebrates most closely related to vertebrates. A recent evolutionary model was proposed in which smooth muscles arose before the last bilaterian common ancestor, and were later diversified, secondarily lost or modified in the branches leading to extant animal taxa. However, there is currently no data from tunicates to support this scenario. METHODS AND RESULTS Here, we show that the axial columnar cells, a unique cell type in the adhesive larval papillae of the tunicate Ciona, are enriched for orthologs of vertebrate smooth/non-muscle-specific effectors of contractility, in addition to developing from progenitors that express conserved cardiomyocyte regulatory factors. We show that these cells contract during the retraction of the Ciona papillae during larval settlement and metamorphosis. CONCLUSIONS We propose that the axial columnar cells of Ciona are a myoepithelial cell type required for transducing external stimuli into mechanical forces that aid in the attachment of the motile larva to its final substrate. Furthermore, they share developmental and functional features with vertebrate myoepithelial cells, vascular smooth muscle cells, and cardiomyocytes. We discuss these findings in the context of the proposed models of vertebrate smooth muscle and cardiomyocyte evolution.
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Nishikawa A, Hanashima A, Nakayama S, Ogasawara M, Kimura S. Transcripts of the nebulin gene from Ciona heart and their implications for the evolution of nebulin family genes. Gene X 2019; 716:144036. [DOI: 10.1016/j.gene.2019.144036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/27/2019] [Accepted: 07/31/2019] [Indexed: 10/26/2022] Open
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Razy-Krajka F, Stolfi A. Regulation and evolution of muscle development in tunicates. EvoDevo 2019; 10:13. [PMID: 31249657 PMCID: PMC6589888 DOI: 10.1186/s13227-019-0125-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 06/08/2019] [Indexed: 12/16/2022] Open
Abstract
For more than a century, studies on tunicate muscle formation have revealed many principles of cell fate specification, gene regulation, morphogenesis, and evolution. Here, we review the key studies that have probed the development of all the various muscle cell types in a wide variety of tunicate species. We seize this occasion to explore the implications and questions raised by these findings in the broader context of muscle evolution in chordates.
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Affiliation(s)
- Florian Razy-Krajka
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, USA
| | - Alberto Stolfi
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, USA
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Rasmussen JP, English K, Tenlen J, Priess JR. Notch signaling and morphogenesis of single-cell tubes in the C. elegans digestive tract. Dev Cell 2008; 14:559-69. [PMID: 18410731 PMCID: PMC2435507 DOI: 10.1016/j.devcel.2008.01.019] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 10/22/2007] [Accepted: 01/31/2008] [Indexed: 11/19/2022]
Abstract
During organogenesis of the C. elegans digestive system, epithelial cells within a cyst-like primordium develop diverse shapes through largely unknown mechanisms. We here analyze two adjacent, dorsal epithelial cells, called pm8 and vpi1, that remodel their shapes and apical junctions to become donut-shaped, or toroidal, single-cell tubes. pm8 and vpi1 delaminate from the dorsal cyst epithelium and migrate ventrally, across the midline of the cyst, on a transient tract of laminin. pm8 appears to encircle the midline by wrapping around finger-like projections from neighboring cells. Finally, pm8 and vpi1 self-fuse to become toroids by expressing AFF-1 and EFF-1, two fusogens that are each sufficient to promote crossfusion between other cell types. Notch signaling in pm8 induces AFF-1 expression, while simultaneously repressing EFF-1 expression; vpi1 expresses EFF-1 independent of Notch. Thus, the adjacent pm8 and vpi1 cells express different fusogens, allowing them to self-fuse into separate, single-cell tubes while avoiding crossfusion.
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Affiliation(s)
- Jeffrey P. Rasmussen
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Howard Hughes Medical Institute
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| | - Kathryn English
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Howard Hughes Medical Institute
| | - Jennifer Tenlen
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Howard Hughes Medical Institute
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| | - James R. Priess
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Howard Hughes Medical Institute
- Department of Biology, University of Washington, Seattle, WA 98195, USA
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Abstract
The primitive chordate Ciona intestinalis has emerged as a significant model system for the study of heart development. The Ciona embryo employs a conserved heart gene network in the context of extremely low cell numbers and reduced genetic redundancy. Here, I review recent studies on the molecular genetics of Ciona cardiogenesis as well as classic work on heart anatomy and physiology. I also discuss the potential of employing Ciona to decipher a comprehensive chordate gene network and to determine how this network controls heart morphogenesis.
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Affiliation(s)
- Brad Davidson
- Department of Molecular and Cellular Biology, Division of Genetics & Development, University of California, Berkeley, CA 94720, United States.
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Meedel T, Hastings K. Striated muscle-type tropomyosin in a chordate smooth muscle, ascidian body-wall muscle. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53314-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Burighel P, Martinucci GB, Lane NJ, Dallai R. Junctional complexes of the branchia and gut of the tunicate, Pyrosoma atlanticum (Pyrosomatida, Thaliacea). Cell Tissue Res 1992. [DOI: 10.1007/bf00302974] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Balser EJ, Ruppert EE. Structure, Ultrastructure, and Function of the Preoral Heart-Kidney inSaccoglossus kowalevskii(Hemichordata, Enteropneusta) Including New Data on the Stomochord. ACTA ZOOL-STOCKHOLM 1990. [DOI: 10.1111/j.1463-6395.1990.tb01082.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Structure, ultrastructure, and function of the terminal organ of a pelagosphera larva (Sipuncula). ZOOMORPHOLOGY 1983. [DOI: 10.1007/bf00363806] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Reuter M. Ultrastructure of the Stylet Protractor Muscle inGyratrix hermaphroditus(Turbellaria, Rhabdocoela). ACTA ZOOL-STOCKHOLM 1977. [DOI: 10.1111/j.1463-6395.1977.tb00253.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Burighel P, Nunzi MG, Schiaffino S. A comparative study of the organization of the sarcotubular system in ascidian muscle. J Morphol 1977; 153:205-23. [PMID: 894724 DOI: 10.1002/jmor.1051530204] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Markwald RR, Fitzharris TP, Manasek FJ. Structural development of endocardial cushions. THE AMERICAN JOURNAL OF ANATOMY 1977; 148:85-119. [PMID: 842477 DOI: 10.1002/aja.1001480108] [Citation(s) in RCA: 320] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Development of chick and rat endocardial cushions (cardiac mesenchyme) was studied histologically (using Nomarski differential interference optics on living and unfixed tissue), ultrastructurally (scanning and transmission electron microscopy), cytochemically (using acidified dialyzed iron as a visual probe for polyanionic material) and autoradiographically (using 35S) to elucidate the origin of the mesenchyme, the morphologic sequences leading to cushion formation and secretion of sulfated glycosaminoglycans, if any, by migrating mesenchymal cells. Cushion formation was similar for both species. Mesenchymal cells appeared initially, in 16- to 18-somite embryos, beneath the endothelium (which lacked a basal lamina) of the future atrioventricular canal and outflow tract. The cytoplasm of cushion mesenchymal cells was structurally similar to the ensothelium; probably these cells arose by proliferation of the endothelium. Mitotic figures among the "seeded" cells were also numerous. Cushion cells were initially attached to the endothelium by desmosomes but acquired motile apparatus (pseudopodia and filopodia containing microtubules and microfilamentous bundles). Serial sectioning of successively-aged embryos (20-44 somites) indicated a centrifugal migratory direction. Interaction of the cell processes with extracellular matrix suggested that the latter was used as a migratory substrate. Contact of the advancing wedge of cushion cells with the myocardium produced no alteration in cell structure or mitotic activity. Localization of hyaluronidase-sensitive, dialyzed iron (DI) precipitates in 250-nm Golgi vacuoles and hyaluronidase-sensitive 35S-endangendered silver grains over cushion cells indicated that this tissue contributed sulfated macromolecules to the matrix. Localization of hyaluronidase-labile, DI material in coated, endocytic-like vesicles and caveolae also suggested potential modification or conditioning of the matrix by migrating mesenchymal cells. Altogether, the study established loci in developing cushions where disruption where disruption of the developmental sequence could engender valvular or septal defects.
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Sur la structure des parois de l'appareil circulatoire dePhoronis psammophila Cori (Phoronida, Lophophorata). ACTA ACUST UNITED AC 1977. [DOI: 10.1007/bf01007603] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Bone Q, Ryan KP. On the structure and innervation of the muscle bands of Doliolum (Tunicata: Cyclomyaria). PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON. SERIES B, BIOLOGICAL SCIENCES 1974; 187:315-27. [PMID: 4154453 DOI: 10.1098/rspb.1974.0077] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The ultrastructure of the muscle fibres composing the circular muscle bands of
Doliolum
is described; these muscle fibres are obliquely striated. Each fibre is elongate and multinucleate; peripherally the myofibrillar array borders the fibre, centrally there are long mitochondria with tubular cristae, and vesiculated sarcoplasm containing glycogen particles. Neither a sarcoplasmic reticulum, nor invaginations of the sarcolemma are present; in both gonozooid and oozooid stages myelin figures are frequent in mitochondria and sarcolemma. On atrial and external faces of the fibres there are nerve terminals containing electron-lucent vesicles some 50 nm in diameter. The junctional gap is
ca
. 10-20 nm wide and is devoid of the dense layer found in the vertebrate synaptic cleft. Each fibre probably receives a number of nerve terminals. The significance of the organization of the muscle fibres is discussed in relation to their role in the locomotion of the animal, and to the structure of other tunicate muscle fibres.
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Cavey MJ, Cloney RA. Fine structure and differentiation of ascidian muscle, 2. Morphometrics and differentiation of the caudal muscle cells of Distaplia occidentalis tadpoles. J Morphol 1974; 144:23-70. [PMID: 4413472 DOI: 10.1002/jmor.1051440104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Kriebel ME. Action potentials occur only on lumen surface of tunicate myoendothelial cells. ACTA ACUST UNITED AC 1973. [DOI: 10.1016/0300-9629(73)90096-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Cavey MJ, Cloney RA. Fine structure and differentiation of Ascidian muscle. I. Differentiated caudal musculature of Distaplia occidentalis tadpoles. J Morphol 1972; 138:349-73. [PMID: 4264162 DOI: 10.1002/jmor.1051380304] [Citation(s) in RCA: 49] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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