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Mashanov V, Ademiluyi S, Jacob Machado D, Reid R, Janies D. Echinoderm radial glia in adult cell renewal, indeterminate growth, and regeneration. Front Neural Circuits 2023; 17:1258370. [PMID: 37841894 PMCID: PMC10570448 DOI: 10.3389/fncir.2023.1258370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/12/2023] [Indexed: 10/17/2023] Open
Abstract
Echinoderms are a phylum of marine deterostomes with a range of interesting biological features. One remarkable ability is their impressive capacity to regenerate most of their adult tissues, including the central nervous system (CNS). The research community has accumulated data that demonstrates that, in spite of the pentaradial adult body plan, echinoderms share deep similarities with their bilateral sister taxa such as hemichordates and chordates. Some of the new data reveal the complexity of the nervous system in echinoderms. In terms of the cellular architecture, one of the traits that is shared between the CNS of echinoderms and chordates is the presence of radial glia. In chordates, these cells act as the main progenitor population in CNS development. In mammals, radial glia are spent in embryogenesis and are no longer present in adults, being replaced with other neural cell types. In non-mammalian chordates, they are still detected in the mature CNS along with other types of glia. In echinoderms, radial glia also persist into the adulthood, but unlike in chordates, it is the only known glial cell type that is present in the fully developed CNS. The echinoderm radial glia is a multifunctional cell type. Radial glia forms the supporting scaffold of the neuroepithelium, exhibits secretory activity, clears up dying or damaged cells by phagocytosis, and, most importantly, acts as a major progenitor cell population. The latter function is critical for the outstanding developmental plasticity of the adult echinoderm CNS, including physiological cell turnover, indeterminate growth, and a remarkable capacity to regenerate major parts following autotomy or traumatic injury. In this review we summarize the current knowledge on the organization and function of the echinoderm radial glia, with a focus on the role of this cell type in adult neurogenesis.
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Affiliation(s)
- Vladimir Mashanov
- Wake Forest Institute for Regenerative Medicine, Winston-Salem, NC, United States
| | - Soji Ademiluyi
- Department of Bioinformatics and Genomics, College of Computing and Informatics, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Denis Jacob Machado
- Department of Bioinformatics and Genomics, College of Computing and Informatics, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Robert Reid
- Department of Bioinformatics and Genomics, College of Computing and Informatics, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Daniel Janies
- Department of Bioinformatics and Genomics, College of Computing and Informatics, University of North Carolina at Charlotte, Charlotte, NC, United States
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2
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Suvorov A. Modalities of aging in organisms with different strategies of resource allocation. Ageing Res Rev 2022; 82:101770. [PMID: 36330930 PMCID: PMC10435286 DOI: 10.1016/j.arr.2022.101770] [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: 06/23/2022] [Revised: 08/17/2022] [Accepted: 10/24/2022] [Indexed: 01/31/2023]
Abstract
Although the progress of aging research relies heavily on a theoretical framework, today there is no consensus on many critical questions in aging biology. I hypothesize that a systematic analysis of the intersection of different evolutionary mechanisms of aging with diverse resource allocation strategies in different organisms may reconcile aging hypotheses. The application of disposable soma, mutation accumulation, antagonistic pleiotropy, and life-history theory is considered across organisms with asexual reproduction, organisms with sexual reproduction and indeterminate growth in different conditions of extrinsic mortality, and organisms with determinate growth, with endotherms/homeotherms as a subgroup. This review demonstrates that different aging mechanisms are complementary to each other, and in organisms with different resource allocation strategies they form aging modalities ranging from immortality to suicidal programs. It also revamps the role of growth arrest in aging. Growth arrest evolved in many different groups of organisms as a result of resource reallocation from growth to reproduction (e.g., semelparous animals, holometabolic insects), or from growth to nutrient storage (endotherms/homeotherms). Growth arrest in different animal lineages has similar molecular mechanisms and similar consequences for longevity due to the conflict between growth-promoting and growth-suppressing programs and suppression of regenerative capacity.
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Affiliation(s)
- Alexander Suvorov
- Environmental Health Sciences, University of Massachusetts, Amherst 240B Goessmann, 686 Noth Pleasant Str., Amherst, MA 01003, USA.
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3
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Sîrbulescu RF, Ilieş I, Amelung L, Zupanc GKH. Proteomic characterization of spontaneously regrowing spinal cord following injury in the teleost fish Apteronotus leptorhynchus, a regeneration-competent vertebrate. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:671-706. [PMID: 36445471 DOI: 10.1007/s00359-022-01591-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/30/2022] [Accepted: 11/01/2022] [Indexed: 11/30/2022]
Abstract
In adult mammals, spontaneous repair after spinal cord injury (SCI) is severely limited. By contrast, teleost fish successfully regenerate injured axons and produce new neurons from adult neural stem cells after SCI. The molecular mechanisms underlying this high regenerative capacity are largely unknown. The present study addresses this gap by examining the temporal dynamics of proteome changes in response to SCI in the brown ghost knifefish (Apteronotus leptorhynchus). Two-dimensional difference gel electrophoresis (2D DIGE) was combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and tandem mass spectrometry (MS/MS) to collect data during early (1 day), mid (10 days), and late (30 days) phases of regeneration following caudal amputation SCI. Forty-two unique proteins with significant differences in abundance between injured and intact control samples were identified. Correlation analysis uncovered six clusters of spots with similar expression patterns over time and strong conditional dependences, typically within functional families or between isoforms. Significantly regulated proteins were associated with axon development and regeneration; proliferation and morphogenesis; neuronal differentiation and re-establishment of neural connections; promotion of neuroprotection, redox homeostasis, and membrane repair; and metabolism or energy supply. Notably, at all three time points examined, significant regulation of proteins involved in inflammatory responses was absent.
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Affiliation(s)
- Ruxandra F Sîrbulescu
- School of Engineering and Science, Jacobs University Bremen, 28725, Bremen, Germany
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, 02115, USA
- Vaccine and Immunotherapy Center, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02129, USA
| | - Iulian Ilieş
- School of Humanities and Social Sciences, Jacobs University Bremen, 28725, Bremen, Germany
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, 02115, USA
| | - Lisa Amelung
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, 02115, USA
| | - Günther K H Zupanc
- School of Engineering and Science, Jacobs University Bremen, 28725, Bremen, Germany.
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, 02115, USA.
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4
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Flury JM, Hilgers L, Herder F, Spanke T, Misof B, Wowor D, Boneka F, Wantania LL, Mokodongan DF, Mayer C, Nolte AW, Schwarzer J. The genetic basis of a novel reproductive strategy in Sulawesi ricefishes: How modularity and a low number of loci shape pelvic brooding. Evolution 2022; 76:1033-1051. [PMID: 35334114 DOI: 10.1111/evo.14475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 01/21/2022] [Accepted: 01/29/2022] [Indexed: 01/21/2023]
Abstract
The evolution of complex phenotypes like reproductive strategies is challenging to understand, as they often depend on multiple adaptations that only jointly result in a specific functionality. Sulawesi ricefishes (Adrianichthyidae) evolved a reproductive strategy termed as pelvic brooding. In contrast to the more common transfer brooding, female pelvic brooders carry an egg bundle connected to their body for weeks until the fry hatches. To examine the genetic architecture of pelvic brooding, we crossed the pelvic brooding Oryzias eversi and the transfer brooding Oryzias nigrimas (species divergence time: ∼3.6 my). We hypothesize, that a low number of loci and modularity have facilitated the rapid evolution of pelvic brooding. Traits associated to pelvic brooding, like rib length, pelvic fin length, and morphology of the genital papilla, were correlated in the parental species but correlations were reduced or lost in their F1 and F2 hybrids. Using the Castle-Wright estimator, we found that generally few loci underlie the studied traits. Further, both parental species showed modularity in their body plans. In conclusion, morphological traits related to pelvic brooding were based on a few loci and the mid-body region likely could evolve independently from the remaining body parts. Both factors presumably facilitated the evolution of pelvic brooding.
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Affiliation(s)
- Jana M Flury
- Leibniz Institute for the Analysis of Biodiversity Change, Zoological Research Museum Alexander Koenig, Bonn, Germany
| | - Leon Hilgers
- Leibniz Institute for the Analysis of Biodiversity Change, Zoological Research Museum Alexander Koenig, Bonn, Germany.,LOEWE Centre for Translational Biodiversity Genomics, Frankfurt, Germany
| | - Fabian Herder
- Leibniz Institute for the Analysis of Biodiversity Change, Zoological Research Museum Alexander Koenig, Bonn, Germany
| | - Tobias Spanke
- Leibniz Institute for the Analysis of Biodiversity Change, Zoological Research Museum Alexander Koenig, Bonn, Germany
| | - Bernhard Misof
- Leibniz Institute for the Analysis of Biodiversity Change, Zoological Research Museum Alexander Koenig, Bonn, Germany
| | - Daisy Wowor
- Museum Zoologicum Bogoriense, Research Center for Biosystematic and Evolution, National Research and Innovation Agency (BRIN), Cibinong, West Java, Indonesia
| | - Farnis Boneka
- Faculty of Fisheries and Marine Science, Sam Ratulangi University, Manado, Indonesia
| | - Letha Louisiana Wantania
- Leibniz Institute for the Analysis of Biodiversity Change, Zoological Research Museum Alexander Koenig, Bonn, Germany.,Faculty of Fisheries and Marine Science, Sam Ratulangi University, Manado, Indonesia
| | - Daniel F Mokodongan
- Museum Zoologicum Bogoriense, Research Center for Biosystematic and Evolution, National Research and Innovation Agency (BRIN), Cibinong, West Java, Indonesia
| | - Christoph Mayer
- Leibniz Institute for the Analysis of Biodiversity Change, Zoological Research Museum Alexander Koenig, Bonn, Germany
| | - Arne W Nolte
- Carl von Ossietzky Universität, Oldenburg, Germany
| | - Julia Schwarzer
- Leibniz Institute for the Analysis of Biodiversity Change, Zoological Research Museum Alexander Koenig, Bonn, Germany
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5
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Modeling of sustained spontaneous network oscillations of a sexually dimorphic brainstem nucleus: the role of potassium equilibrium potential. J Comput Neurosci 2021; 49:419-439. [PMID: 34032982 DOI: 10.1007/s10827-021-00789-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/15/2021] [Accepted: 04/29/2021] [Indexed: 10/21/2022]
Abstract
Intrinsic oscillators in the central nervous system play a preeminent role in the neural control of rhythmic behaviors, yet little is known about how the ionic milieu regulates their output patterns. A powerful system to address this question is the pacemaker nucleus of the weakly electric fish Apteronotus leptorhynchus. A neural network comprised of an average of 87 pacemaker cells and 20 relay cells produces tonic oscillations, with higher frequencies in males compared to females. Previous empirical studies have suggested that this sexual dimorphism develops and is maintained through modulation of buffering of extracellular K+ by a massive meshwork of astrocytes enveloping the pacemaker and relay cells. Here, we constructed a model of this neural network that can generate sustained spontaneous oscillations. Sensitivity analysis revealed the potassium equilibrium potential, EK (as a proxy of extracellular K+ concentration), and corresponding somatic channel conductances as critical determinants of oscillation frequency and amplitude. In models of both the pacemaker nucleus network and isolated pacemaker and relay cells, the frequency increased almost linearly with EK, whereas the amplitude decreased nonlinearly with increasing EK. Our simulations predict that this frequency increase is largely caused by a shift in the minimum K+ conductance over one oscillation period. This minimum is close to zero at more negative EK, converging to the corresponding maximum at less negative EK. This brings the resting membrane potential closer to the threshold potential at which voltage-gated Na+ channels become active, increasing the excitability, and thus the frequency, of pacemaker and relay cells.
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6
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Zupanc GKH. Adult neurogenesis in the central nervous system of teleost fish: from stem cells to function and evolution. J Exp Biol 2021; 224:258585. [PMID: 33914040 DOI: 10.1242/jeb.226357] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Adult neurogenesis, the generation of functional neurons from adult neural stem cells in the central nervous system (CNS), is widespread, and perhaps universal, among vertebrates. This phenomenon is more pronounced in teleost fish than in any other vertebrate taxon. There are up to 100 neurogenic sites in the adult teleost brain. New cells, including neurons and glia, arise from neural stem cells harbored both in neurogenic niches and outside these niches (such as the ependymal layer and parenchyma in the spinal cord, respectively). At least some, but not all, of the stem cells are of astrocytic identity. Aging appears to lead to stem cell attrition in fish that exhibit determinate body growth but not in those with indeterminate growth. At least in some areas of the CNS, the activity of the neural stem cells results in additive neurogenesis or gliogenesis - tissue growth by net addition of cells. Mathematical and computational modeling has identified three factors to be crucial for sustained tissue growth and correct formation of CNS structures: symmetric stem cell division, cell death and cell drift due to population pressure. It is hypothesized that neurogenesis in the CNS is driven by continued growth of corresponding muscle fibers and sensory receptor cells in the periphery to ensure a constant ratio of peripheral versus central elements. This 'numerical matching hypothesis' can explain why neurogenesis has ceased in most parts of the adult CNS during the evolution of mammals, which show determinate growth.
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Affiliation(s)
- Günther K H Zupanc
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA 02115, USA
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7
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Frýdlová P, Mrzílková J, Šeremeta M, Křemen J, Dudák J, Žemlička J, Minnich B, Kverková K, Němec P, Zach P, Frynta D. Determinate growth is predominant and likely ancestral in squamate reptiles. Proc Biol Sci 2020; 287:20202737. [PMID: 33352069 PMCID: PMC7779497 DOI: 10.1098/rspb.2020.2737] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Body growth is typically thought to be indeterminate in ectothermic vertebrates. Indeed, until recently, this growth pattern was considered to be ubiquitous in ectotherms. Our recent observations of a complete growth plate cartilage (GPC) resorption, a reliable indicator of arrested skeletal growth, in many species of lizards clearly reject the ubiquity of indeterminate growth in reptiles and raise the question about the ancestral state of the growth pattern. Using X-ray micro-computed tomography (µCT), here we examined GPCs of long bones in three basally branching clades of squamate reptiles, namely in Gekkota, Scincoidea and Lacertoidea. A complete loss of GPC, indicating skeletal growth arrest, was the predominant finding. Using a dataset of 164 species representing all major clades of lizards and the tuataras, we traced the evolution of determinate growth on the phylogenetic tree of Lepidosauria. The reconstruction of character states suggests that determinate growth is ancestral for the squamate reptiles (Squamata) and remains common in the majority of lizard lineages, while extended (potentially indeterminate) adult growth evolved several times within squamates. Although traditionally associated with endotherms, determinate growth is coupled with ectothermy in this lineage. These findings combined with existing literature suggest that determinate growth predominates in both extant and extinct amniotes.
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Affiliation(s)
- Petra Frýdlová
- Department of Zoology, Faculty of Science, Charles University, Prague 12844, Czech Republic.,Department of Anatomy, Third Faculty of Medicine, Charles University, Prague 100 00, Czech Republic
| | - Jana Mrzílková
- Specialized Laboratory of Experimental Imaging, Third Faculty of Medicine of Charles University, Institute of Technical and Applied Physics and Faculty of Bioengineering, Prague 100 00, Czech Republic.,Department of Anatomy, Third Faculty of Medicine, Charles University, Prague 100 00, Czech Republic
| | - Martin Šeremeta
- Specialized Laboratory of Experimental Imaging, Third Faculty of Medicine of Charles University, Institute of Technical and Applied Physics and Faculty of Bioengineering, Prague 100 00, Czech Republic.,Department of Anatomy, Third Faculty of Medicine, Charles University, Prague 100 00, Czech Republic
| | - Jan Křemen
- Specialized Laboratory of Experimental Imaging, Third Faculty of Medicine of Charles University, Institute of Technical and Applied Physics and Faculty of Bioengineering, Prague 100 00, Czech Republic.,Department of Anatomy, Third Faculty of Medicine, Charles University, Prague 100 00, Czech Republic
| | - Jan Dudák
- Institute of Experimental and Applied Physics, Czech Technical University in Prague, Prague 110 00, Czech Republic
| | - Jan Žemlička
- Institute of Experimental and Applied Physics, Czech Technical University in Prague, Prague 110 00, Czech Republic
| | - Bernd Minnich
- Department of Biosciences, University of Salzburg, Hellbrunnerstrasse 34, Salzburg 5020, Austria
| | - Kristina Kverková
- Department of Zoology, Faculty of Science, Charles University, Prague 12844, Czech Republic
| | - Pavel Němec
- Department of Zoology, Faculty of Science, Charles University, Prague 12844, Czech Republic
| | - Petr Zach
- Specialized Laboratory of Experimental Imaging, Third Faculty of Medicine of Charles University, Institute of Technical and Applied Physics and Faculty of Bioengineering, Prague 100 00, Czech Republic.,Department of Anatomy, Third Faculty of Medicine, Charles University, Prague 100 00, Czech Republic
| | - Daniel Frynta
- Department of Zoology, Faculty of Science, Charles University, Prague 12844, Czech Republic
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8
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Holland ND, Somorjai IML. Serial blockface SEM suggests that stem cells may participate in adult notochord growth in an invertebrate chordate, the Bahamas lancelet. EvoDevo 2020; 11:22. [PMID: 33088474 PMCID: PMC7568382 DOI: 10.1186/s13227-020-00167-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 10/07/2020] [Indexed: 01/07/2023] Open
Abstract
Background The cellular basis of adult growth in cephalochordates (lancelets or amphioxus) has received little attention. Lancelets and their constituent organs grow slowly but continuously during adult life. Here, we consider whether this slow organ growth involves tissue-specific stem cells. Specifically, we focus on the cell populations in the notochord of an adult lancelet and use serial blockface scanning electron microscopy (SBSEM) to reconstruct the three-dimensional fine structure of all the cells in a tissue volume considerably larger than normally imaged with this technique. Results In the notochordal region studied, we identified 10 cells with stem cell-like morphology at the posterior tip of the organ, 160 progenitor (Müller) cells arranged along its surface, and 385 highly differentiated lamellar cells constituting its core. Each cell type could clearly be distinguished on the basis of cytoplasmic density and overall cell shape. Moreover, because of the large sample size, transitions between cell types were obvious. Conclusions For the notochord of adult lancelets, a reasonable interpretation of our data indicates growth of the organ is based on stem cells that self-renew and also give rise to progenitor cells that, in turn, differentiate into lamellar cells. Our discussion compares the cellular basis of adult notochord growth among chordates in general. In the vertebrates, several studies implied that proliferating cells (chordoblasts) in the cortex of the organ might be stem cells. However, we think it is more likely that such cells actually constitute a progenitor population downstream from and maintained by inconspicuous stem cells. We venture to suggest that careful searches should find stem cells in the adult notochords of many vertebrates, although possibly not in the notochordal vestiges (nucleus pulposus regions) of mammals, where the presence of endogenous proliferating cells remains controversial.
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Affiliation(s)
- Nicholas D Holland
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California At San Diego, La Jolla, CA 92093 USA
| | - Ildiko M L Somorjai
- School of Biology, University of Saint Andrews, St. Andrews, KY16 9ST Scotland
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9
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Lehotzky D, Sipahi R, Zupanc GKH. Cellular automata modeling suggests symmetric stem-cell division, cell death, and cell drift as key mechanisms driving adult spinal cord growth in teleost fish. J Theor Biol 2020; 509:110474. [PMID: 32918922 DOI: 10.1016/j.jtbi.2020.110474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 08/10/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022]
Abstract
Adult neurogenesis - the generation of neurons during adulthood - is intensively studied, yet little is known about its consequences at the tissue level. In the teleost fish Apteronotus leptorhynchus, morphometric analysis has revealed that the total number of cells in the spinal cord increases continuously throughout adulthood, driven by the activity of neurogenic stem/progenitor cells in both the ependymal layer at the central canal and in the radially located parenchyma. This net increase in cell numbers demonstrates cellular addition, as opposed to cellular turnover which appears to be the common outcome of adult neurogenesis in mammals. Grounded on a comprehensive set of quantitative data generated through high-resolution mapping of stem cells and their progeny, we constructed a cellular automata model of the stem-cell-driven growth of the spinal cord. Simulations based on this model suggest that three cellular mechanisms play a critical role for promoting sustained tissue growth and acquisition of correct form of the spinal cord, including the development of the ependymal layer and the parenchyma: the number of symmetric stem-cell divisions versus asymmetric divisions; the probability of the progeny of progenitor cells to undergo cell death; and the radial drifting of cells.
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Affiliation(s)
- Dávid Lehotzky
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, United States.
| | - Rifat Sipahi
- Complex Dynamic Systems and Control Laboratory, Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, United States.
| | - Günther K H Zupanc
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, United States.
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10
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Zupanc GKH. Development of a sexual dimorphism in a central pattern generator driving a rhythmic behavior: The role of glia-mediated potassium buffering in the pacemaker nucleus of the weakly electric fish Apteronotus leptorhynchus. Dev Neurobiol 2020; 80:6-15. [PMID: 32090501 DOI: 10.1002/dneu.22736] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 01/24/2020] [Accepted: 02/20/2020] [Indexed: 01/09/2023]
Abstract
Central pattern generators play a critical role in the neural control of rhythmic behaviors. One of their characteristic features is the ability to modulate the oscillatory output. An important yet little-studied type of modulation involves the generation of oscillations that are sexually dimorphic in frequency. In the weakly electric fish Apteronotus leptorhynchus, the pacemaker nucleus serves as a central pattern generator that drives the electric organ discharge of the fish in a one-to-one fashion. Males discharge at higher frequencies than females-a sexual dimorphism that develops under the influence of steroid hormones. The two principal neurons that constitute the oscillatory network of the pacemaker nucleus are the pacemaker and relay cells. Whereas the number and size of the pacemaker and relay cells are sexually monomorphic, pronounced sex-dependent differences exist in the morphology, and subcellular properties of astrocytes, which form a syncytium closely associated with these neurons. In females, compared to males, the astrocytic syncytium covers a larger area surrounding the pacemaker and relay cells and exhibits higher levels of expression of connexin-43 expression. The latter indicates a strong gap-junction coupling of the individual cells within the syncytium. It is hypothesized that these sex-specific differences result in an increased capacity for buffering of extracellular potassium ions, thereby lowering the potassium equilibrium potential, which, in turn, leads to a decrease in the oscillation frequency. This hypothesis has received strong support from simulations based on computational models of individual neurons and the whole neural network of the pacemaker nucleus.
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Affiliation(s)
- Günther K H Zupanc
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, Massachusetts, USA
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11
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Zupanc GKH, Monaghan JR, Stocum DL. Adult Neural Stem Cells in Development, Regeneration, and Aging. Dev Neurobiol 2020; 79:391-395. [PMID: 31219240 DOI: 10.1002/dneu.22702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 05/22/2019] [Indexed: 12/25/2022]
Affiliation(s)
| | - James R Monaghan
- Department of Biology, Northeastern University, Boston, Massachusetts
| | - David L Stocum
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana
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12
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Frýdlová P, Mrzílková J, Šeremeta M, Křemen J, Dudák J, Žemlička J, Němec P, Velenský P, Moravec J, Koleška D, Zahradníčková V, Jirásek T, Kodym P, Frynta D, Zach P. Universality of indeterminate growth in lizards rejected: the micro-CT reveals contrasting timing of growth cartilage persistence in iguanas, agamas, and chameleons. Sci Rep 2019; 9:18913. [PMID: 31831851 PMCID: PMC6908584 DOI: 10.1038/s41598-019-54573-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 11/06/2019] [Indexed: 02/06/2023] Open
Abstract
Squamate reptiles are considered to exhibit indeterminate growth. Nevertheless, current literature disputes the available definitions of this growth type, presents new theoretical models, and questions its universality in cold-blooded vertebrates. We have followed up on our previous research employing micro-CT to explore growth plate cartilage (GPC) in the epiphysis of long bones, which is responsible for longitudinal skeletal growth by the endochondral ossification process. We focused on numerous and highly diversified group of the Iguania clade comprising Acrodonta (agamas and chameleons) and Pleurodonta ("iguanas"). We recorded the absence of GPC in most of the examined adult Pleurodonta specimens and interpret it as an irreversible arrest of skeletal growth. This finding clearly rejects the universality of indeterminate growth in lizards. On the other hand, we found apparent GPC preservation in most of the adult specimens belonging to Acrodonta. This suggests a preserved ability to continue body growth throughout most of their life. We discuss the uncovered disparity between Acrodonta and Pleurodonta and emphasize the importance of GPC degradation timing.
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Affiliation(s)
- Petra Frýdlová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-12844, Prague, Czech Republic
- Department of Anatomy, Third Faculty of Medicine, Charles University, Ruská 2411/87, CZ-10000, Prague, Czech Republic
| | - Jana Mrzílková
- Specialized laboratory of experimental imaging, Ruská 2411/87, CZ-10000, Prague, Czech Republic
- Department of Anatomy, Third Faculty of Medicine, Charles University, Ruská 2411/87, CZ-10000, Prague, Czech Republic
| | - Martin Šeremeta
- Specialized laboratory of experimental imaging, Ruská 2411/87, CZ-10000, Prague, Czech Republic
- Department of Anatomy, Third Faculty of Medicine, Charles University, Ruská 2411/87, CZ-10000, Prague, Czech Republic
| | - Jan Křemen
- Specialized laboratory of experimental imaging, Ruská 2411/87, CZ-10000, Prague, Czech Republic
- Department of Anatomy, Third Faculty of Medicine, Charles University, Ruská 2411/87, CZ-10000, Prague, Czech Republic
| | - Jan Dudák
- Institute of Experimental and Applied Physics, Czech Technical University in Prague, Husova 5, CZ-11000, Prague, Czech Republic
| | - Jan Žemlička
- Institute of Experimental and Applied Physics, Czech Technical University in Prague, Husova 5, CZ-11000, Prague, Czech Republic
| | - Pavel Němec
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-12844, Prague, Czech Republic
| | - Petr Velenský
- Prague Zoo, U Trojského Zámku 3, CZ-17100, Prague, Czech Republic
| | - Jiří Moravec
- Department of Zoology, National Museum, Cirkusová 1740, CZ-19300, Prague, Czech Republic
| | - Daniel Koleška
- Department of Zoology and Fisheries, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, CZ-16500, Prague, Czech Republic
| | - Veronika Zahradníčková
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-12844, Prague, Czech Republic
| | - Tomáš Jirásek
- Zoological and Botanical Garden Pilsen, Pod Vinicemi 9, CZ-30116, Pilsen, Czech Republic
| | - Petr Kodym
- National Institute of Public Health, Šrobárova 48, CZ-10042, Prague, Czech Republic
| | - Daniel Frynta
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-12844, Prague, Czech Republic.
| | - Petr Zach
- Specialized laboratory of experimental imaging, Ruská 2411/87, CZ-10000, Prague, Czech Republic
- Department of Anatomy, Third Faculty of Medicine, Charles University, Ruská 2411/87, CZ-10000, Prague, Czech Republic
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13
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Vitalo AG, Ilieş I, Zupanc GKH. Calbindin-D 28k expression in spinal electromotoneurons of the weakly electric fish Apteronotus leptorhynchus during adult development and regeneration. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:595-608. [PMID: 31165281 DOI: 10.1007/s00359-019-01343-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 04/29/2019] [Accepted: 05/04/2019] [Indexed: 12/01/2022]
Abstract
Additive neurogenesis, the net increase in neuronal numbers by addition of new nerve cells to existing tissue, forms the basis for indeterminate spinal cord growth in brown ghost knifefish (Apteronotus leptorhynchus). Among the cells generated through the activity of adult neural stem cells are electromotoneurons, whose axons constitute the electric organ of this weakly electric fish. Electromotoneuron development is organized along a caudo-rostral gradient, with the youngest and smallest of these cells located near the caudal end of the spinal cord. Electromotoneurons start expressing calbindin-D28k when their somata have reached diameters of approximately 10 μm, and they continue expression after they have grown to a final size of about 50 μm. Calbindin-D28k expression is significantly increased in young neurons generated in response to injury. Immunohistochemical staining against caspase-3 revealed that electromotoneurons in both intact and regenerating spinal cord are significantly less likely to undergo apoptosis than the average spinal cord cell. We hypothesize that expression of calbindin-D28k protects electromotoneurons from cell death; and that the evolutionary development of such a neuroprotective mechanism has been driven by the indispensability of electromotoneurons in the fish's electric behavior, and by the high size-dependent costs associated with their production or removal upon cell death.
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Affiliation(s)
- Antonia G Vitalo
- Laboratory of Neurobiology, Department of Biology, Northeastern University, 134 Mugar Life Sciences, 360 Huntington Avenue, Boston, MA, 02115, USA
| | - Iulian Ilieş
- Healthcare Systems Engineering Institute, Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Günther K H Zupanc
- Laboratory of Neurobiology, Department of Biology, Northeastern University, 134 Mugar Life Sciences, 360 Huntington Avenue, Boston, MA, 02115, USA.
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14
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Zupanc GK, Zupanc FB, Sipahi R. Stochastic cellular automata model of tumorous neurosphere growth: Roles of developmental maturity and cell death. J Theor Biol 2019; 467:100-110. [DOI: 10.1016/j.jtbi.2019.01.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 12/13/2018] [Accepted: 01/19/2019] [Indexed: 02/06/2023]
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15
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Zupanc GK. Stem‐Cell‐Driven Growth and Regrowth of the Adult Spinal Cord in Teleost Fish. Dev Neurobiol 2019; 79:406-423. [DOI: 10.1002/dneu.22672] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 02/12/2019] [Accepted: 02/25/2019] [Indexed: 01/08/2023]
Affiliation(s)
- Günther K.H. Zupanc
- Laboratory of Neurobiology, Department of Biology Northeastern University Boston Massachusetts
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16
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Freitas PD, Yandulskaya AS, Monaghan JR. Spinal Cord Regeneration in Amphibians: A Historical Perspective. Dev Neurobiol 2019; 79:437-452. [PMID: 30725532 DOI: 10.1002/dneu.22669] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 01/22/2019] [Accepted: 01/25/2019] [Indexed: 12/11/2022]
Abstract
In some vertebrates, a grave injury to the central nervous system (CNS) results in functional restoration, rather than in permanent incapacitation. Understanding how these animals mount a regenerative response by activating resident CNS stem cell populations is of critical importance in regenerative biology. Amphibians are of a particular interest in the field because the regenerative ability is present throughout life in urodele species, but in anuran species it is lost during development. Studying amphibians, who transition from a regenerative to a nonregenerative state, could give insight into the loss of ability to recover from CNS damage in mammals. Here, we highlight the current knowledge of spinal cord regeneration across vertebrates and identify commonalities and differences in spinal cord regeneration between amphibians.
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Affiliation(s)
- Polina D Freitas
- Department of Biology, Northeastern University, 360 Huntington Ave., 134 Mugar Hall, Boston, Massachusetts, 02115
| | - Anastasia S Yandulskaya
- Department of Biology, Northeastern University, 360 Huntington Ave., 134 Mugar Hall, Boston, Massachusetts, 02115
| | - James R Monaghan
- Department of Biology, Northeastern University, 360 Huntington Ave., 134 Mugar Hall, Boston, Massachusetts, 02115
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17
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Edwards-Faret G, Cebrián-Silla A, Méndez-Olivos EE, González-Pinto K, García-Verdugo JM, Larraín J. Cellular composition and organization of the spinal cord central canal during metamorphosis of the frog Xenopus laevis. J Comp Neurol 2018; 526:1712-1732. [PMID: 29603210 DOI: 10.1002/cne.24441] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/12/2018] [Accepted: 03/21/2018] [Indexed: 01/12/2023]
Abstract
Studying the cellular composition and morphological changes of cells lining the central canal during Xenopus laevis metamorphosis could contribute to understand postnatal development and spinal cord regeneration. Here we report the analysis of central canal cells at different stages during metamorphosis using immunofluorescence for protein markers expression, transmission and scanning electron microscopy and cell proliferation assays. The central canal was regionalized according to expression of glial markers, ultrastructure, and proliferation in dorsal, lateral, and ventral domains with differences between larvae and froglets. In regenerative larvae, all cell types were uniciliated, have a radial morphology, and elongated nuclei with lax chromatin, resembling radial glial cells. Important differences in cells of nonregenerative froglets were observed, although uniciliated cells were found, the most abundant cells had multicilia and revealed extensive changes in the maturation and differentiation state. The majority of dividing cells in larvae corresponded to uniciliated cells at dorsal and lateral domains in a cervical-lumbar gradient, correlating with undifferentiated features. Neurons contacting the lumen of the central canal were detected in both stages and revealed extensive changes in the maturation and differentiation state. However, in froglets a very low proportion of cells incorporate 5-ethynyl-2'-deoxyuridine (EdU), associated with the differentiated profile and with the increase of multiciliated cells. Our work showed progressive changes in the cell types lining the central canal of Xenopus laevis spinal cord which are correlated with the regenerative capacities.
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Affiliation(s)
- Gabriela Edwards-Faret
- Center for Aging and Regeneration, Faculty of Biological Sciences, P. Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Arantxa Cebrián-Silla
- Laboratorio de Neurobiologia Comparada, Instituto Cavanilles, Universidad de Valencia, Valencia 46980, CIBERNED, Valencia, Spain
| | - Emilio E Méndez-Olivos
- Center for Aging and Regeneration, Faculty of Biological Sciences, P. Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Karina González-Pinto
- Center for Aging and Regeneration, Faculty of Biological Sciences, P. Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile.,Universidad Arturo Prat del Estado de Chile, Iquique, Chile
| | - José Manuel García-Verdugo
- Laboratorio de Neurobiologia Comparada, Instituto Cavanilles, Universidad de Valencia, Valencia 46980, CIBERNED, Valencia, Spain
| | - Juan Larraín
- Center for Aging and Regeneration, Faculty of Biological Sciences, P. Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
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18
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Zupanc GKH. Dynamic Neuron-Glia Interactions in an Oscillatory Network Controlling Behavioral Plasticity in the Weakly Electric Fish, Apteronotus leptorhynchus. Front Physiol 2017; 8:1087. [PMID: 29311998 PMCID: PMC5744004 DOI: 10.3389/fphys.2017.01087] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/11/2017] [Indexed: 11/16/2022] Open
Abstract
The involvement of glial cells in the regulation of physiological functions is being increasingly recognized, yet their role in plasticity of neural oscillators has remained largely elusive. An excellent model system to address the latter function is the pacemaker nucleus of the weakly electric fish, Apteronotus leptorhynchus. This brainstem oscillator drives the fish's electric organ discharge in a one-to-one fashion, with median frequencies of 880 Hz in males and 740 Hz in females. Morphometric analysis of the pacemaker nucleus has shown that astrocytes outnumber mature neurons seven-fold, and oscillator neurons even 200-fold. A similar dominance of astrocytes occurs among the adult-born cells that differentiate into glia and neurons. The astrocytes form a dense meshwork of cells interconnected by gap junctions. The degree of association of astrocytic fibers with the neural oscillator cells, and the gap-junction coupling between individual astrocytes, exhibit a sexual dimorphism, which parallels the sexual dimorphisms in the output frequency of the pacemaker nucleus, and ultimately in the electric organ discharge of the fish. It is hypothesized that the dynamics in astroglial structure mediate differences in the capacity to buffer potassium, which increases during the generation of action potentials. These differences, in turn, affect the excitability of the neural oscillator cells, and thus the output frequency of the pacemaker nucleus. Comparison of the pacemaker nucleus with other brain oscillators suggests that modulation of the output activity is one of the chief functions of the interaction of glia with the neural oscillator cells.
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Affiliation(s)
- Günther K H Zupanc
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, United States
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19
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Ilieş I, Sipahi R, Zupanc GKH. Growth of adult spinal cord in knifefish: Development and parametrization of a distributed model. J Theor Biol 2017; 437:101-114. [PMID: 29031516 DOI: 10.1016/j.jtbi.2017.10.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 10/08/2017] [Accepted: 10/11/2017] [Indexed: 12/12/2022]
Abstract
The study of indeterminate-growing organisms such as teleost fish presents a unique opportunity for improving our understanding of central nervous tissue growth during adulthood. Integrating the existing experimental data associated with this process into a theoretical framework through mathematical or computational modeling provides further research avenues through sensitivity analysis and optimization. While this type of approach has been used extensively in investigations of tumor growth, wound healing, and bone regeneration, the development of nervous tissue has been rarely studied within a modeling framework. To address this gap, the present work introduces a distributed model of spinal cord growth in the knifefish Apteronotus leptorhynchus, an established teleostean model of adult growth in the central nervous system. The proposed model incorporates two mechanisms, cell proliferation by active stem/progenitor cells and cell drift due to population pressure, both of which are subject to global constraints. A coupled reaction-diffusion equation approach was adopted to represent the densities of actively-proliferating and non-proliferating cells along the longitudinal axis of the spinal cord. Computer simulations using this model yielded biologically-feasible growth trajectories. Subsequent comparisons with whole-organism growth curves allowed the estimation of previously-unknown parameters, such as relative growth rates.
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Affiliation(s)
- Iulian Ilieş
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, USA
| | - Rifat Sipahi
- Complex Dynamic Systems and Control Laboratory, Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, USA
| | - Günther K H Zupanc
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, USA.
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