1
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Tsissios G, Sallese A, Perez-Estrada JR, Tangeman JA, Chen W, Smucker B, Ratvasky SC, Grajales-Esquivel E, Martinez A, Visser KJ, Joven Araus A, Wang H, Simon A, Yun MH, Del Rio-Tsonis K. Macrophages modulate fibrosis during newt lens regeneration. Stem Cell Res Ther 2024; 15:141. [PMID: 38745238 PMCID: PMC11094960 DOI: 10.1186/s13287-024-03740-1] [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: 11/15/2023] [Accepted: 04/23/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND Previous studies have suggested that macrophages are present during lens regeneration in newts, but their role in the process is yet to be elucidated. METHODS Here we generated a transgenic reporter line using the newt, Pleurodeles waltl, that traces macrophages during lens regeneration. Furthermore, we assessed early changes in gene expression during lens regeneration using two newt species, Notophthalmus viridescens and Pleurodeles waltl. Finally, we used clodronate liposomes to deplete macrophages during lens regeneration in both species and tested the effect of a subsequent secondary injury after macrophage recovery. RESULTS Macrophage depletion abrogated lens regeneration, induced the formation of scar-like tissue, led to inflammation, decreased iris pigment epithelial cell (iPEC) proliferation, and increased rates of apoptosis in the eye. Some of these phenotypes persisted throughout the last observation period of 100 days and could be attenuated by exogenous FGF2 administration. A distinct transcript profile encoding acute inflammatory effectors was established for the dorsal iris. Reinjury of the newt eye alleviated the effects of macrophage depletion, including the resolution of scar-like tissue, and re-initiated the regeneration process. CONCLUSIONS Together, our findings highlight the importance of macrophages for facilitating a pro-regenerative environment in the newt eye by regulating fibrotic responses, modulating the overall inflammatory landscape, and maintaining the proper balance of early proliferation and late apoptosis of the iPECs.
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Affiliation(s)
- Georgios Tsissios
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at, Miami University, Oxford, OH, USA
- Cellular Molecular and Structural Biology Program, Miami University, Oxford, OH, USA
| | - Anthony Sallese
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at, Miami University, Oxford, OH, USA
| | - J Raul Perez-Estrada
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at, Miami University, Oxford, OH, USA
| | - Jared A Tangeman
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at, Miami University, Oxford, OH, USA
- Cellular Molecular and Structural Biology Program, Miami University, Oxford, OH, USA
| | - Weihao Chen
- Center for Visual Sciences at, Miami University, Oxford, OH, USA
- Cellular Molecular and Structural Biology Program, Miami University, Oxford, OH, USA
- Department of Chemical, Paper and Biomedical Engineering, Miami University, Oxford, OH, USA
| | - Byran Smucker
- Center for Visual Sciences at, Miami University, Oxford, OH, USA
- Department of Statistics, Miami University, Oxford, OH, USA
| | - Sophia C Ratvasky
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at, Miami University, Oxford, OH, USA
- Cellular Molecular and Structural Biology Program, Miami University, Oxford, OH, USA
| | - Erika Grajales-Esquivel
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at, Miami University, Oxford, OH, USA
| | - Arielle Martinez
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at, Miami University, Oxford, OH, USA
| | - Kimberly J Visser
- CRTD/ Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
| | - Alberto Joven Araus
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Hui Wang
- Center for Visual Sciences at, Miami University, Oxford, OH, USA
- Department of Chemical, Paper and Biomedical Engineering, Miami University, Oxford, OH, USA
| | - András Simon
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Maximina H Yun
- CRTD/ Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, Dresden, Germany
| | - Katia Del Rio-Tsonis
- Department of Biology, Miami University, Oxford, OH, USA.
- Center for Visual Sciences at, Miami University, Oxford, OH, USA.
- Cellular Molecular and Structural Biology Program, Miami University, Oxford, OH, USA.
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2
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Tsissios G, Sallese A, Perez-Estrada JR, Tangeman JA, Chen W, Smucker B, Ratvasky SC, Grajales-Esquive EL, Martinez A, Visser KJ, Araus AJ, Wang H, Simon A, Yun MH, Rio-Tsonis KD. Macrophages modulate fibrosis during newt lens regeneration. RESEARCH SQUARE 2023:rs.3.rs-3603645. [PMID: 38045376 PMCID: PMC10690311 DOI: 10.21203/rs.3.rs-3603645/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Background Previous studies indicated that macrophages play a role during lens regeneration in newts, but their function has not been tested experimentally. Methods Here we generated a transgenic newt reporter line in which macrophages can be visualized in vivo. Using this new tool, we analyzed the location of macrophages during lens regeneration. We uncovered early gene expression changes using bulk RNAseq in two newt species, Notophthalmus viridescens and Pleurodeles waltl. Next, we used clodronate liposomes to deplete macrophages, which inhibited lens regeneration in both newt species. Results Macrophage depletion induced the formation of scar-like tissue, an increased and sustained inflammatory response, an early decrease in iris pigment epithelial cell (iPEC) proliferation and a late increase in apoptosis. Some of these phenotypes persisted for at least 100 days and could be rescued by exogenous FGF2. Re-injury alleviated the effects of macrophage depletion and re-started the regeneration process. Conclusions Together, our findings highlight the importance of macrophages in facilitating a pro-regenerative environment in the newt eye, helping to resolve fibrosis, modulating the overall inflammatory landscape and maintaining the proper balance of early proliferation and late apoptosis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Maximina H Yun
- Dresden University of Technology: Technische Universitat Dresden
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3
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Tsissios G, Sallese A, Perez-Estrada JR, Tangeman JA, Chen W, Smucker B, Ratvasky SC, Grajales-Esquivel E, Martinez A, Visser KJ, Araus AJ, Wang H, Simon A, Yun MH, Rio-Tsonis KD. Macrophages modulate fibrosis during newt lens regeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.04.543633. [PMID: 37333184 PMCID: PMC10274724 DOI: 10.1101/2023.06.04.543633] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Previous studies indicated that macrophages play a role during lens regeneration in newts, but their function has not been tested experimentally. Here we generated a transgenic newt reporter line in which macrophages can be visualized in vivo. Using this new tool, we analyzed the location of macrophages during lens regeneration. We uncovered early gene expression changes using bulk RNAseq in two newt species, Notophthalmus viridescens and Pleurodeles waltl. Next, we used clodronate liposomes to deplete macrophages, which inhibited lens regeneration in both newt species. Macrophage depletion induced the formation of scar-like tissue, an increased and sustained inflammatory response, an early decrease in iris pigment epithelial cell (iPEC) proliferation and a late increase in apoptosis. Some of these phenotypes persisted for at least 100 days and could be rescued by exogenous FGF2. Re-injury alleviated the effects of macrophage depletion and re-started the regeneration process. Together, our findings highlight the importance of macrophages in facilitating a pro-regenerative environment in the newt eye, helping to resolve fibrosis, modulating the overall inflammatory landscape and maintaining the proper balance of early proliferation and late apoptosis.
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Affiliation(s)
- Georgios Tsissios
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at Miami University, Oxford, OH, USA
- Cellular Molecular and Structural Biology Program, Miami University, Oxford, OH, USA
| | - Anthony Sallese
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at Miami University, Oxford, OH, USA
| | - J Raul Perez-Estrada
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at Miami University, Oxford, OH, USA
| | - Jared A Tangeman
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at Miami University, Oxford, OH, USA
- Cellular Molecular and Structural Biology Program, Miami University, Oxford, OH, USA
| | - Weihao Chen
- Center for Visual Sciences at Miami University, Oxford, OH, USA
- Cellular Molecular and Structural Biology Program, Miami University, Oxford, OH, USA
- Department of Chemical, Paper and Biomedical Engineering, Miami University, Oxford, OH, USA
| | - Byran Smucker
- Center for Visual Sciences at Miami University, Oxford, OH, USA
- Department of Statistics, Miami University, Oxford, OH, USA
| | - Sophia C Ratvasky
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at Miami University, Oxford, OH, USA
- Cellular Molecular and Structural Biology Program, Miami University, Oxford, OH, USA
| | - Erika Grajales-Esquivel
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at Miami University, Oxford, OH, USA
| | - Arielle Martinez
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at Miami University, Oxford, OH, USA
| | - Kimberly J Visser
- CRTD Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
| | - Alberto Joven Araus
- Karolinska Institute, Department of Cell and Molecular Biology, Stockholm, Sweden
| | - Hui Wang
- Center for Visual Sciences at Miami University, Oxford, OH, USA
- Department of Chemical, Paper and Biomedical Engineering, Miami University, Oxford, OH, USA
| | - Andras Simon
- Karolinska Institute, Department of Cell and Molecular Biology, Stockholm, Sweden
| | - Maximina H Yun
- CRTD Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, Dresden, Germany
| | - Katia Del Rio-Tsonis
- Department of Biology, Miami University, Oxford, OH, USA
- Center for Visual Sciences at Miami University, Oxford, OH, USA
- Cellular Molecular and Structural Biology Program, Miami University, Oxford, OH, USA
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4
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Mitra AT, Womack MC, Gower DJ, Streicher JW, Clark B, Bell RC, Schott RK, Fujita MK, Thomas KN. Ocular lens morphology is influenced by ecology and metamorphosis in frogs and toads. Proc Biol Sci 2022; 289:20220767. [PMID: 36382525 PMCID: PMC9667364 DOI: 10.1098/rspb.2022.0767] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The shape and relative size of an ocular lens affect the focal length of the eye, with consequences for visual acuity and sensitivity. Lenses are typically spherical in aquatic animals with camera-type eyes and axially flattened in terrestrial species to facilitate vision in optical media with different refractive indices. Frogs and toads (Amphibia: Anura) are ecologically diverse, with many species shifting from aquatic to terrestrial ecologies during metamorphosis. We quantified lens shape and relative size using 179 micro X-ray computed tomography scans of 126 biphasic anuran species and tested for correlations with life stage, environmental transitions, adult habits and adult activity patterns. Across broad phylogenetic diversity, tadpole lenses are more spherical than those of adults. Biphasic species with aquatic larvae and terrestrial adults typically undergo ontogenetic changes in lens shape, whereas species that remain aquatic as adults tend to retain more spherical lenses after metamorphosis. Further, adult lens shape is influenced by adult habit; notably, fossorial adults tend to retain spherical lenses following metamorphosis. Finally, lens size relative to eye size is smaller in aquatic and semiaquatic species than other adult ecologies. Our study demonstrates how ecology shapes visual systems, and the power of non-invasive imaging of museum specimens for studying sensory evolution.
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Affiliation(s)
- Amartya T. Mitra
- Division of Biosciences, University College London, London, UK
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
| | - Molly C. Womack
- Department of Biology, Utah State University, Logan, UT 84322, USA
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0162, USA
| | - David J. Gower
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
| | | | - Brett Clark
- Imaging and Analysis Centre, The Natural History Museum, London SW7 5BD, UK
| | - Rayna C. Bell
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0162, USA
- Department of Herpetology, California Academy of Sciences, San Francisco, CA 94118, USA
| | - Ryan K. Schott
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0162, USA
- Department of Biology and Centre for Vision Research, York University, Toronto, Ontario, Canada
| | - Matthew K. Fujita
- Department of Biology, Amphibian and Reptile Diversity Research Center, The University of Texas at Arlington, Arlington, TX 76019, USA
| | - Kate N. Thomas
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
- Department of Biology, Amphibian and Reptile Diversity Research Center, The University of Texas at Arlington, Arlington, TX 76019, USA
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5
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Eye and Skin Differences between Atelognathus patagonicus Morphotypes: Two Environments, Two Strategies (Anura; Batrachylidae). J HERPETOL 2022. [DOI: 10.1670/20-081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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6
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Pelych LN, Shellabarger W, Vassallo M, Noland E, Sledge D, Aquino SE. Ophthalmic findings in a captive population of Panamanian golden frogs:
Atelopus zeteki. Vet Ophthalmol 2019; 22:430-439. [DOI: 10.1111/vop.12609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 07/16/2018] [Accepted: 07/19/2018] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | - Erica Noland
- Diagnostic Center for Population and Animal Health Michigan State University East Lansing Michigan
| | - Dodd Sledge
- Diagnostic Center for Population and Animal Health Michigan State University East Lansing Michigan
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7
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Abstract
In this review, we compare and contrast the three different forms of vertebrate lens regeneration: Wolffian lens regeneration, cornea-lens regeneration, and lens regeneration from lens epithelial cells. An examination of the diverse cellular origins of these lenses, their unique phylogenetic distribution, and the underlying molecular mechanisms, suggests that these different forms of lens regeneration evolved independently and utilize neither conserved nor convergent mechanisms to regulate these processes.
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Affiliation(s)
- Jonathan J Henry
- Department of Cell and Developmental Biology, University of Illinois, Urbana, IL
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8
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Tseng AS. Seeing the future: usingXenopusto understand eye regeneration. Genesis 2017; 55. [DOI: 10.1002/dvg.23003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 11/15/2016] [Accepted: 11/16/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Ai-Sun Tseng
- School of Life Sciences; University of Nevada; Las Vegas, 4505 South Maryland Parkway, Box 454004 Las Vegas Nevada 89154
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9
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Markitantova YV, Zinovieva RD. Intracellular localization of transcription factor PROX1 in the human retina in ontogeny. BIOL BULL+ 2014. [DOI: 10.1134/s106235901402006x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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10
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Grigoryan EN, Markitantova YV, Avdonin PP, Radugina EA. Study of regeneration in amphibians in age of molecular-genetic approaches and methods. RUSS J GENET+ 2013. [DOI: 10.1134/s1022795413010043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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11
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Retina and lens regeneration in anuran amphibians. Semin Cell Dev Biol 2009; 20:528-34. [DOI: 10.1016/j.semcdb.2008.11.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 11/07/2008] [Accepted: 11/18/2008] [Indexed: 11/19/2022]
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12
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Abstract
The neural retina in teleost fish can regenerate after surgical or neurotoxic destruction. Whereas in amphibians the retina regenerates by transdifferentiation of pigmented retinal epithelial cells, in goldfish (Carassius auratus) the source of regenerated retinal cells is a population of scattered proliferating cells located in the outer nuclear layer within the differentiated retina. These proliferating cells are modified neuroepithelial cells termed 'rod precursors' because in the intact retina they produce only rod photoreceptor cells and do so continuously, inserting new rods into the growing adult retina. Although rod precursors normally exhibit a restricted developmental fate they appear not to be committed to the rod lineage. When retinal neurons are destroyed, rod precursors cease producing rods and give rise to clusters of primitive neuroepithelial cells which divide vigorously and reconstitute the retina in an orderly temporal pattern that mimics the process of normal development. Only after production of cones and other retinal neurons has ceased do rod precursors again appear and resume the generation of rods. We conclude that rod precursors respond to local cues in their environment that regulate the differentiation and choice of cell fate by their progeny.
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Affiliation(s)
- P A Raymond
- Department of Anatomy & Cell Biology, University of Michigan Medical School, Ann Arbor 48109-0616
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13
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Yoshii C, Ueda Y, Okamoto M, Araki M. Neural retinal regeneration in the anuran amphibian Xenopus laevis post-metamorphosis: transdifferentiation of retinal pigmented epithelium regenerates the neural retina. Dev Biol 2006; 303:45-56. [PMID: 17184765 DOI: 10.1016/j.ydbio.2006.11.024] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 10/10/2006] [Accepted: 11/16/2006] [Indexed: 11/18/2022]
Abstract
In urodele amphibians like the newt, complete retina and lens regeneration occurs throughout their lives. In contrast, anuran amphibians retain this capacity only in the larval stage and quickly lose it during metamorphosis. It is believed that they are unable to regenerate these tissues after metamorphosis. However, contrary to this generally accepted notion, here we report that both the neural retina (NR) and lens regenerate following the surgical removal of these tissues in the anuran amphibian, Xenopus laevis, even in the mature animal. The NR regenerated both from the retinal pigment epithelial (RPE) cells by transdifferentiation and from the stem cells in the ciliary marginal zone (CMZ) by differentiation. In the early stage of NR regeneration (5-10 days post operation), RPE cells appeared to delaminate from the RPE layer and adhere to the remaining retinal vascular membrane. Thereafter, they underwent transdifferentiation to regenerate the NR layer. An in vitro culture study also revealed that RPE cells differentiated into neurons and that this was accelerated by the presence of FGF-2 and IGF-1. The source of the regenerating lens appeared to be remaining lens epithelium, suggesting that this is a kind of repair process rather than regeneration. Thus, we show for the first time that anuran amphibians retain the capacity for retinal regeneration after metamorphosis, similarly to urodeles, but that the mode of regeneration differs between the two orders. Our study provides a new tool for the molecular analysis of regulatory mechanisms involved in retinal and lens regeneration by providing an alternative animal model to the newt, the only other experimental model.
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Affiliation(s)
- Chika Yoshii
- Developmental Neurobiology Laboratory, Department of Biological Sciences, Nara Women's University, Nara 630-8506, Japan
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14
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Madhavan M, Haynes TL, Frisch NC, Call MK, Minich CM, Tsonis PA, Del Rio-Tsonis K. The role of Pax-6 in lens regeneration. Proc Natl Acad Sci U S A 2006; 103:14848-53. [PMID: 17003134 PMCID: PMC1595439 DOI: 10.1073/pnas.0601949103] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pax-6 is a master regulator of eye development and is expressed in the dorsal and ventral iris during newt lens regeneration. We show that expression of Pax-6 during newt lens regeneration coincides with cell proliferation. By knocking down expression of Pax-6 via treatment with morpholinos, we found that proliferation of iris pigment epithelial cells was dramatically reduced both in vitro and in vivo, and, as a result, lens regeneration was significantly retarded. However, induction of dedifferentiation in the dorsal iris was not inhibited. Pax-6 knockdown early in lens regeneration resulted in inhibition of crystallin expression and retardation of lens fiber induction. Once crystallin expression and differentiation of lens fibers has ensued, however, loss of function of Pax-6 did not affect crystallin expression and lens fiber maintenance, even though the effects on proliferation persisted. These results conclusively show that Pax-6 is associated with distinct early events during lens regeneration, namely control of cell proliferation and subsequent lens fiber differentiation.
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Affiliation(s)
- Mayur Madhavan
- *Department of Zoology, Miami University, Oxford, OH 45056; and
| | - Tracy L. Haynes
- *Department of Zoology, Miami University, Oxford, OH 45056; and
| | | | - Mindy K. Call
- Laboratory of Molecular Biology, Department of Biology, University of Dayton, Dayton, OH 45469
| | - Craig M. Minich
- *Department of Zoology, Miami University, Oxford, OH 45056; and
| | - Panagiotis A. Tsonis
- Laboratory of Molecular Biology, Department of Biology, University of Dayton, Dayton, OH 45469
- To whom correspondence may be addressed. E-mail:
or
| | - Katia Del Rio-Tsonis
- *Department of Zoology, Miami University, Oxford, OH 45056; and
- To whom correspondence may be addressed. E-mail:
or
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15
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Arresta E, Bernardini S, Bernardini E, Filoni S, Cannata SM. Pigmented epithelium to retinal transdifferentiation and Pax6 expression in larval Xenopus laevis. ACTA ACUST UNITED AC 2006; 303:958-67. [PMID: 16217804 DOI: 10.1002/jez.a.219] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study examines the retinal transdifferentiation (TD) of retinal pigmented epithelium (RPE) fragments dissected from Xenopus laevis larvae and implanted into the vitreous chamber of non-lentectomized host eyes. In these experimental conditions, most RPE implants transformed into polarized vesicles in which the side adjacent to the lens maintained the RPE phenotype, while the side adjacent to the host retina transformed into a laminar retina with the photoreceptor layer facing the cavity of the vesicle and with the ganglionar cell layer facing the host retina. The formation of a new retina with a laminar organization is the result of depigmentation, proliferation and differentiation of progenitor cells under the influence of inductive factors from the host retina. The phases of the TD process were followed using BrdU labelling as a marker of the proliferation phase and using a monoclonal antibody (mAbHP1) as a definitive indicator of retina formation. Pigmented RPE cells do not express Pax6. In the early phase of RPE to retinal TD, all depigmented and proliferating progenitor cells expressed Pax6. Changes in the Pax6 expression pattern became apparent in the early phase of differentiation, when Pax6 expression decreased in the presumptive outer nuclear layer (ONL) of the new-forming retina. Finally, during the late differentiation phase, the ONL, which contains photoreceptors, no longer expressed Pax6, Pax6 expression being confined to the ganglion cell layer and the inner nuclear layer. These results indicate that Pax6 may have different roles during the different phases of RPE to retinal TD, acting as an early retinal determinant and later directing progenitor cell fate.
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Affiliation(s)
- Emiliano Arresta
- Dipartimento di Biologia, Università di Roma "Tor Vergata", I-00133 Rome, Italy
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16
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Mitsuda S, Yoshii C, Ikegami Y, Araki M. Tissue interaction between the retinal pigment epithelium and the choroid triggers retinal regeneration of the newt Cynops pyrrhogaster. Dev Biol 2005; 280:122-32. [PMID: 15766753 DOI: 10.1016/j.ydbio.2005.01.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2004] [Revised: 01/06/2005] [Accepted: 01/12/2005] [Indexed: 11/18/2022]
Abstract
Complete retinal regeneration in adult animals occurs only in certain urodele amphibians, in which the retinal pigmented epithelial cells (RPE) undergo transdifferentiation to produce all cell types constituting the neural retina. A similar mechanism also appears to be involved in retinal regeneration in the embryonic stage of some other species, but the nature of this mechanism has not yet been elucidated. The organ culture model of retinal regeneration is a useful experimental system and we previously reported RPE transdifferentiation of the newt under this condition. Here, we show that cultured RPE cells proliferate and differentiate into neurons when cultured with the choroid attached to the RPE, but they did not exhibit any morphological changes when cultured alone following removal of the choroid. This finding indicates that the tissue interactions between the RPE and the choroid are essential for the former to proliferate. This tissue interaction appears to be mediated by diffusible factors, because the choroid could affect RPE cells even when the two tissues were separated by a membrane filter. RPE transdifferentiation under the organotypic culture condition was abolished by a MEK (ERK kinase) inhibitor, U0126, but was partially suppressed by an FGF receptor inhibitor, SU5402, suggesting that FGF signaling pathway has a central role in the transdifferentiation. While IGF-1 alone had no effect on isolated RPE, combination of FGF-2 and IGF-1 stimulated RPE cell transdifferentiation similar to the results obtained in organ-cultured RPE and choroid. RT-PCR revealed that gene expression of both FGF-2 and IGF-1 is up-regulated following removal of the retina. Thus, we show for the first time that the choroid plays an essential role in newt retinal regeneration, opening a new avenue for understanding the molecular mechanisms underlying retinal regeneration.
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Affiliation(s)
- Sanae Mitsuda
- Developmental Neurobiology Laboratory, Department of Biological Sciences, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
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17
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Tsonis PA, Vergara MN, Spence JR, Madhavan M, Kramer EL, Call MK, Santiago WG, Vallance JE, Robbins DJ, Del Rio-Tsonis K. A novel role of the hedgehog pathway in lens regeneration. Dev Biol 2004; 267:450-61. [PMID: 15013805 DOI: 10.1016/j.ydbio.2003.12.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2003] [Revised: 12/01/2003] [Accepted: 12/01/2003] [Indexed: 10/26/2022]
Abstract
Lens regeneration in the adult newt is a classic example of replacing a lost organ by the process of transdifferentiation. After lens removal, the pigmented epithelial cells of the dorsal iris proliferate and dedifferentiate to form a lens vesicle, which subsequently differentiates to form a new lens. In searching for factors that control this remarkable process, we investigated the expression and role of hedgehog pathway members. These molecules are known to affect retina and pigment epithelium morphogenesis and have been recently shown to be involved in repair processes. Here we show that Shh, Ihh, ptc-1, and ptc-2 are expressed during lens regeneration. The expression of Shh and Ihh is quite unique since these genes have never been detected in lens. Interestingly, both Shh and Ihh are only expressed in the regenerating and developing lens, but not in the intact lens. Interfering with the hedgehog pathway results in considerable inhibition of the process of lens regeneration, including decreased cell proliferation as well as interference with lens fiber differentiation in the regenerating lens vesicle. Down-regulation of ptc-1 was also observed when inhibiting the pathway. These results provide the first evidence of a novel role for the hedgehog pathway in specific regulation of the regenerating lens.
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Affiliation(s)
- Panagiotis A Tsonis
- Laboratory of Molecular Biology, Department of Biology, University of Dayton, Dayton, OH 45469-2320, USA.
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18
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Abstract
Eye tissues such as the lens and the retina possess remarkable regenerative abilities. In amphibians, a complete lens can be regenerated after lentectomy. The process is a classic example of transdifferentiation of one cell type to another. Likewise, retina can be regenerated, but the strategy used to replace the damaged retina differs, depending on the animal system and the age of the animal. Retina can be regenerated by transdifferentiation or by the use of stem cells. In this review, we present a synthesis on the regenerative capacity of eye tissues in different animals with emphasis on the strategy and the molecules involved. In addition, we stress the place of this field at the molecular age and the importance of the recent technologic advances.
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Henry JJ. The cellular and molecular bases of vertebrate lens regeneration. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 228:195-265. [PMID: 14667045 DOI: 10.1016/s0074-7696(03)28005-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Lens regeneration takes place in some vertebrates through processes of cellular dedifferentiation and transdifferentiation, processes by which certain differentiated cell types can give rise to others. This review describes the principal forms of lens regeneration that occur in vivo as well as related in vitro systems of transdifferentiation. Classic experimental studies are reviewed that define the tissue interactions that trigger these events in vivo. Recent molecular analyses have begun to identify the genes associated with these processes. These latter studies generally reveal tremendous similarities between embryonic lens development and lens regeneration. Different models are proposed to describe basic molecular pathways that define the processes of lens regeneration and transdifferentiation. Finally, studies are discussed suggesting that fibroblast growth factors play key roles in supporting the process of lens regeneration. Retinoids, such as retinoic acid, may also play important roles in this process.
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Affiliation(s)
- Jonathan J Henry
- Department of Cell and Structural Biology, University of Illinois, Urbana, Illinois 61801, USA
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20
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Shekhawat DS, Jangir OP, Prakash A, Pawan S. Lens regeneration in mice under the influence of vitamin A. J Biosci 2001; 26:571-6. [PMID: 11807287 DOI: 10.1007/bf02704755] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The effect of vitamin A has been studied on lens regeneration in young (7 days old) as well as adult mice. A longitudinal slit was made under local anesthesia in the cornea over the lens. The lens was extracted intact through the incision. Intraperitonial injection of vitamin A (0.05 ml of 30 IU/ml in young and 0.05 ml of 50 IU/ml in adult) was given to the operated animals. Vitamin A was found to induce lens regeneration in not only young but also in adult mice. Regenerated lenses were similar in shape, size, transparency and histological features to normal intact lenses.
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Affiliation(s)
- D S Shekhawat
- Developmental Biology Laboratory, Department of Zoology, Dungar College, Bikaner 334 001, India
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21
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Affiliation(s)
- P A Raymond
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor 48109-0616, USA
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22
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Tamalu F, Chiba C, Ishida AT, Saito T. Functional differentiation of ganglion cells from multipotent progenitor cells in sliced retina of adult goldfish. J Comp Neurol 2000; 419:297-305. [PMID: 10723006 DOI: 10.1002/(sici)1096-9861(20000410)419:3<297::aid-cne3>3.0.co;2-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Multipotent progenitor cells at the retinal margin of adult goldfish give rise to all cell types in the rest of the retina. We took advantage of this spatial arrangement of progenitor and mature cells in slices of peripheral retina, to investigate the appearance and maturation of voltage-activated Na(+) current. We divided the peripheral retina into three broad regions (marginal, intermediate, and mature) on the basis of their morphological development. Whole-cell patch-clamp recordings were performed in ruptured-patch mode, so that cells from which currents were recorded could be identified by Lucifer Yellow fills. No voltage-activated Na(+) current was detected in the slender, peripherally located marginal cells. Voltage-activated Na(+) currents were detected in rounded cells found alongside or near marginal cells, facing the vitreal side of the retina. Some of these "intermediate cells" had a long axon-like process which ran along the vitreal surface. Intermediate cells adjacent to the marginal region tended to have smaller Na(+) currents than intermediate cells closer to the mature region. On average, the maximum Na(+) current amplitude recorded from intermediate cells was roughly 6-fold smaller than that of mature ganglion cells. In addition, the activation threshold of the Na(+) current in intermediate cells was nearly 14 mV more positive than that of mature ganglion cells. The results indicate that voltage-activated Na(+) current, as a possible marker of retinal ganglion cells, begins to develop well before these cells migrate to their adult position within the retina.
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Affiliation(s)
- F Tamalu
- Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572 Japan
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23
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Ito M, Hayashi T, Kuroiwa A, Okamoto M. Lens formation by pigmented epithelial cell reaggregate from dorsal iris implanted into limb blastema in the adult newt. Dev Growth Differ 1999; 41:429-40. [PMID: 10466930 DOI: 10.1046/j.1440-169x.1999.00447.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In newt lens regeneration, the dorsal iris has lens forming ability and the ventral iris has no such capability, whereas there is no difference in the morphological criteria. To investigate the real aspects of this characteristic lens regeneration in the newt at the cellular level, a useful model system was constructed by transplanting the dorsal and ventral reaggregate derived from singly dissociated pigmented epithelial cells of the iris into the blastema of the forelimb in the newt. The lens was formed from the dorsal reaggregate with high efficiency, but not from the ventral one. No lens formation was observed in the implantation of the reaggregate into the tissue of the intact limbs. In detailed examination of the process of lens formation from the reaggregate, it was shown that tubular formation was the first step in the rearrangement of cells within the reaggregate. This was followed by depigmentation, vesicle formation with active cell growth, and the final step was lens fiber formation by transdifferentiation of epithelial cells composing the lens vesicle. The process was almost the same as in situ lens regeneration except the reconstitution of the two-layered epithelial structure was embodied as flattened tubular formation in the first step. The present study made it possible for the first time to examine lens forming ability in the reaggregate mixed with dorsal and ventral cells, because the formation of a reaggregate was started from singly dissociated cells of the dorsal and ventral cells of the iris. Mixed reaggregate experiments indicated that the existence of the dorsal cells in a cluster within the reaggregate is important in lens formation, and ventral cells showed an inhibitory effect on the formation. The present study demonstrated that the limb system thus constructed was effective for the analysis of lens formation at the cellular level and made it possible to examine the role of dorsal and ventral cells in lens regeneration.
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Affiliation(s)
- M Ito
- Division of Biological Science, Graduate School of Science, Nagoya University, Japan
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24
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Jung JC, Del Rio-Tsonis K, Tsonis PA. Regulation of homeobox-containing genes during lens regeneration. Exp Eye Res 1998; 66:361-70. [PMID: 9533863 DOI: 10.1006/exer.1997.0437] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this study, the expression of homeobox-containing genes was evaluated after lentectomy in the newt, which is competent for lens regeneration, and in the axolotl which is not. Such a comparison was designed to offer insights about possible regulation due to regenerative abilities. Six homeobox-containing genes were examined: NvHox A4, NvHox B1, NvHox 7, NvHox X, Nvmsx-1 and Xbr1. For all genes examined, it was found that soon after lentectomy in the newt there was a general down-regulation in the retina. This down-regulation varied among the Hox genes with NvHox 7 and NvHox B1 being virtually absent in the initial stages; their expression was re-established to the original levels after the reappearance of lens. The expression patterns, for NvHox 7 and NvHox B1 were the same when the lens was removed and then displaced. However, in axolotl, down-regulation was not observed. These data suggest that the observed regulation is related to the process of lens regeneration and provide the first molecular evidence that lens regeneration could be dependent on retina and underline the importance of this tissue in lens regeneration. Such patterns link expression of homeobox-containing genes and lens regeneration and can be now used to understand the underlying mechanisms of lens regeneration and transdifferentiation.
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Affiliation(s)
- J C Jung
- Laboratory of Molecular Biology, Department of Biology, University of Dayton, Dayton, OH 45469-2320, USA
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25
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Abstract
Examination of data on the inducing capacity of mesoderm-inducing factors shows that none of them induces mesoderm alone, but that they also induce endoderm and neural tissues, while in the mesoderm itself, they induce tissues belonging to its main levels. Tests on the inducing capacity of living retina have shown that it does not induce mesoderm, but does induce a spectrum of tissues, including retina, pigmented epithelium, lens and a piece of brain. This situation seems to be indispensable because if it evokes only one differentiation, an increase of diversity in development would be impossible. Selectivity occurs only at the end of the sequence of inductions, as it does in the induction of lens tissue by lens epithelium. Such mechanisms, however, are insufficient for the development of different kinds of cells into homogeneous tissues. This is achieved through the aggregation or separation of initially induced cells, their own products determining (or not) their further fate and leading to homogeneity of tissues. These mechanisms of the first two levels of inductive interactions overlap with events that allow or prevent the access of inducing factors and are, therefore, also involved in the manifestation of competence of potentially reactive cells.
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Affiliation(s)
- G V Lopashov
- Institute of Gene Biology, Russian Academy of Science, Moscow
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26
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Sakaguchi DS, Janick LM, Reh TA. Basic fibroblast growth factor (FGF-2) induced transdifferentiation of retinal pigment epithelium: generation of retinal neurons and glia. Dev Dyn 1997; 209:387-98. [PMID: 9264262 DOI: 10.1002/(sici)1097-0177(199708)209:4<387::aid-aja6>3.0.co;2-e] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In the present study we report that basic fibroblast growth factor (bFGF, FGF-2) promotes the transdifferentiation of Xenopus laevis larval retinal pigment epithelium (RPE) into neural retina. Using specific antibodies we have examined the cellular composition of the regenerated retinal tissue. Our results show that, in addition to retinal neurons and photoreceptors, glial cells were also regenerated from the transdifferentiated RPE. These results were specific to FGF-2, since other factors that were tested, including acidic FGF (aFGF, FGF-1), epidermal growth factor (EGF), laminin, ECL, and Matrigel, exhibited no activity in inducing retinal regeneration. These results are the first in amphibians demonstrating the functional role of FGF-2 in inducing RPE transdifferentiation. Transplantation studies were carried out to investigate retinal regeneration from the RPE in an in vivo environment. Sheets of RPE implanted into the lens-less eyes of larval hosts transformed into neurons and glial cells only when under the influence of host retinal factors. In contrast, no retinal transdifferentiation occurred if the RPE was implanted into the enucleated orbit. Taken together, these results show that the amphibian RPE is capable of transdifferentiation into neuronal and glial cell-phenotypes and implicate FGF-2 as an important factor in inducing retinal regeneration in vitro.
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Affiliation(s)
- D S Sakaguchi
- Department of Zoology and Genetics, Iowa State University, Ames 50011, USA.
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27
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Pow DV. Taurine, amino acid transmitters, and related molecules in the retina of the Australian lungfish Neoceratodus forsteri: a light-microscopic immunocytochemical and electron-microscopic study. Cell Tissue Res 1994; 278:311-26. [PMID: 8001086 DOI: 10.1007/bf00414175] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The morphology of the retina of the Australian lungfish Neoceratodus forsteri was investigated by means of light- and electron microscopy, whilst immunocytochemical studies were performed to determine the cellular distributions of the major amino acid neurotransmitters and other amino acids. The distributions of glycine and GABA were similar to those previously described for teleost, amphibian and mammalian retinae. Labelling was abundant in amacrine cells, whilst GABA was also present in one layer of horizontal cells and some bipolar cells. Taurine was present in both rods and cones, but, unlike the mammalian or avian retina, was absent from other cellular structures, including glial elements. Unexpectedly, the photoreceptor terminals lacked an apparent content of the excitatory amino acid transmitter glutamate. The glutamate that was present in the rods and cones occupied a crescentic arc corresponding to the location of glycogen-rich paraboloids. Asparagine was also present in rods, albeit in the modified mitochondria that formed the elipsoids of the rod inner segments. Arginine, the precursor for formation of nitric oxide, was present in glial cells, and in the paraboloids of both rods and cones.
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Affiliation(s)
- D V Pow
- Department of Physiology and Pharmacology, University of Queensland, Brisbane, Australia
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28
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Chapter 9 Lens transdifferentiation in the vertebrate retinal pigmented epithelial cell. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0278-4327(93)90010-q] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Borst DE, McDevitt DS. Eye lens regeneration and the crystallins in the adult newt, Notophthalmus viridescens. Exp Eye Res 1987; 45:419-41. [PMID: 3666065 DOI: 10.1016/s0014-4835(87)80128-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Upon lens removal, the adult Eastern Spotted newt, Notophthalmus viridescens, has the capacity to regenerate an ocular lens. Crystallins, proteins characteristic of the vertebrate lens, were studied from normal and 3-month regenerated adult newt lenses. When separated by high-performance liquid chromatography (HPLC) or Sephadex G-200SF column chromatography, the crystallins from normal and regenerated lenses were fractionated into what appear to be the classical four groups: alpha, beta High, beta Low, and gamma. Upon further examination by immunoelectrophoresis, the first peak contains both alpha and beta crystallins. This study provides evidence that most of the crystallins from the regenerated lenses share biochemical properties with those of the normal lens crystallins based on their native molecular weight, isoelectric point, and the molecular wt of their constituent polypeptides, indicating that the fidelity of gene expression in reactivated iris tissue is high. Some differences are found between normal and regenerated lens crystallins and are most obvious in the beta-crystallin region: the proportion of beta crystallins is decreased in regenerated lenses when the total proteins are fractionated by column chromatography and some of the beta-crystallin polypeptide chains found in normal lenses are missing from regenerated lenses. Iris epithelial cells are normally withdrawn from the cell cycle and are synthesizing a tissue-specific product, melanin. After lentectomy these cells dedifferentiate, redifferentiate into lens cells, and their progeny then synthesize different tissue-specific proteins, crystallins. Little is known about the specific mechanism(s) for the activation of gene expression in eukaryotes, but the regenerating lens suggests itself as a good model in which to study this biological problem.
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Affiliation(s)
- D E Borst
- Department of Animal Biology, University of Pennsylvania, School of Veterinary Medicine 19104
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30
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Itoh Y, Eguchi G. In vitro analysis of cellular metaplasia from pigmented epithelial cells to lens phenotypes: a unique model system for studying cellular and molecular mechanisms of "transdifferentiation". Dev Biol 1986; 115:353-62. [PMID: 3709968 DOI: 10.1016/0012-1606(86)90255-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Pigmented epithelial cells (PECs) were dissociated from eyes of 8- to 9-day-old chick embryos and were cultured in EdF medium (Eagle's MEM supplemented with dialyzed fetal bovine serum) containing phenylthiourea (PTU) and testicular hyaluronidase (HUase). The PECs rapidly lost melanosomes as they proliferated and dedifferentiated in culture. These dedifferentiated PECs (dePECs) which did not manifest any identifiable specificity could be directed to one of two different differentiated phenotypes; viz., lens or pigment cells, depending upon subsequent culture conditions. Almost all dePECs began to synthesize melanin and redifferentiated to PECs by Day 10 of culture with EdF medium containing ascorbic acid (AsA). In contrast, the sister population of dePECs, when cultured at extremely high cell density with EdF medium containing PTU, HUase and AsA, synthesized delta-crystallin which is specific for lens. This transdifferentiation into lens cells occurred by Day 15 of culture. Using this culture system we are able to produce a homogeneous cell population with the potential for synchronous differentiation into either lens or pigment cell phenotype. The system is useful for studying mechanisms involved in cellular metaplasia.
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31
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Eguchi G. Instability in cell commitment of vertebrate pigmented epithelial cells and their transdifferentiation into lens cells. Curr Top Dev Biol 1986; 20:21-37. [PMID: 3514135 DOI: 10.1016/s0070-2153(08)60652-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Abstract
It has been shown that, upon lentectomy or in culture, iris epithelial cells (IECs) of adult newts become converted into lens cells, and this conversion is the basic event of lens regeneration in newts. Whether in situ or in cell culture, the conversion requires the passage of a specific number of cell cycles. The progeny of IECs which fails to traverse this cell-cycle number redifferentiates as IECs in situ. The passage through cell cycles of IECs is associated with progressive alterations of cytoplasm and cell surface, during which the original state of differentiation disappears (dedifferentiation). It is speculated that the altered state of cells caused by proliferation leads to the appearance of factors which interact with the genome and switch the gene activation pattern to that of the lens cell. In this model, developmental controls are geared to the cell-cycle progression and not directly to the activation of lens-characteristic genes. A number of points are raised which speak against the long-held idea that a factor from neural retina induces lens differentiation in IECs. It is proposed that the retinal factor plays the role of growth factor which is essential in the conversion in situ, but not required in the conversion in cell culture. The proposed model is compared with reprogramming of differentiation of some cell lines by cytidine analogs and with ontogenic systems of differentiation control.
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33
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Stroeva OG, Mitashov VI. Retinal pigment epithelium: proliferation and differentiation during development and regeneration. INTERNATIONAL REVIEW OF CYTOLOGY 1983; 83:221-93. [PMID: 6315626 DOI: 10.1016/s0074-7696(08)61689-7] [Citation(s) in RCA: 123] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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34
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McDevitt DS, Brahma SK. alpha-, beta- and gamma-Crystallins in the regenerating lens of Notophthalmus viridescens. Exp Eye Res 1982; 34:587-94. [PMID: 7042379 DOI: 10.1016/0014-4835(82)90032-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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35
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Eguchi G, Masuda A, Karasawa Y, Kodama R, Itoh Y. Microenvironments controlling the transdifferentiation of vertebrate pigmented epithelial cells in in vitro culture. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1982; 158:209-21. [PMID: 7158538 DOI: 10.1007/978-1-4899-5292-9_22] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The transdifferentiation of pigmented epithelial cells in vitro is briefly introduced. Several environmental conditions regulating the process have been demonstrated experimentally. On the basis of these data we have suggested regulatory factors in relation to the mechanisms for the initiation of the transdifferentiation of pigmented epithelial cells, focussing particularly on cell surface functions. Finally, we have presented data which contributes to the establishment of a useful and powerful cell culture system which makes it possible for us to analyse the molecular basis of transdifferentiation.
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Reyer RW. Dedifferentiation of iris epithelium during lens regeneration in newt larvae. THE AMERICAN JOURNAL OF ANATOMY 1982; 163:1-23. [PMID: 7058771 DOI: 10.1002/aja.1001630102] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Early stages in lens regeneration from the pigmented epithelium of the dorsal iris were studied in larval Notophthalmus viridescens by means of transmission electron microscopy. Normal iris epithelium is composed of two layers of low cuboidal cells. packed with melanosomes and surrounded by a basal lamina. Scattered desmosomes attach adjacent cells. Following lens removal, the intercellular spaces enlarge and the epithelial cells increase in size. Some irregular microvilli from these cells extent into the intercellular spaces. Macrophages invade the iris epithelium and phagocytize melanosomes discharged from the pigmented cells. These invading macrophages have numerous microprojections and are often separated from the surface by a very thin layer of iris epithelial cell cytoplasm. In the iris cells, nucleoli become more prominent and granular, polyribosomes increase greatly in number, melanosomes gradually disappear, mitochondria become more numerous, and mitotic activity is greatly augmented. Fine cell processes of adjacent interdigitate near the external surface, where numerous micropinocytotic vesicles can be seen. Over the external surface, the basal lamina may be disrupted or duplicated in places where pseudopodia project from iris cells or a macrophage has entered an intercellular space. It is lacking on the lumenal surface. Sloughed membranes are often found in these intercellular spaces.
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37
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HOPERSKAYA OLGAA, ZVIADADZEZ KETEVANG. Transdifferentiation of Adult Frog Iris in Retina or Lens by Exogeneous Influences. Dev Growth Differ 1981. [DOI: 10.1111/j.1440-169x.1981.00201.x] [Citation(s) in RCA: 9] [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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38
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Gulati AK, Reyer RW. Role of neural retina and vitreous body during lens regeneration: transplantation and autoradiography. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1980; 214:109-18. [PMID: 7462974 DOI: 10.1002/jez.1402140114] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The trophic influence of neural retina in regeneration of the lens from dorsal iris is well known. The first part of this study involved transplantation of dorsal iris pieces into various intra-ocular positions in order to determine the field of action of the neural retina. The most favorable location for lens regeneration was the pupillary space, closely followed by the vitreous chamber. Lens regeneration was retarded from implants lying in the anterior chamber; this was most evident when grafts were placed in front of the iris and not in contact with the swollen vitreous body. Incorporation of 3H-leucine in the neural retina and vitreous body was also investigated using autoradiography. No significant difference in labeling was seen between the control and lentectomized neural retina at all time intervals studied. However, increased labeling above that in the controls was observed over the vitreous body between 8 to 20 days after lentectomy. There was also an increase in the number of silver grains over the vitreous body with increasing time between injection of isotope and sacrifice of the animal. These results provide evidence that vitreous body plays an important role in the process of lens regeneration, perhaps serving as a preferential pathway for transfer of the neural retinal factor to the dorsal iris.
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Gulati AK. Changes in RNA and protein synthesis in the neural retina during lens regeneration in newts. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1980; 214:101-8. [PMID: 6161984 DOI: 10.1002/jez.1402140113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Since neural retina stimulates regeneration of a lens from the dorsal iris in newts, RNA and protein synthesis in the neural retina was investigated during this process. Incorporation of 3H-uridine and 3H-leucine using liquid scintillation counting was employed to compare RNA and protein synthesis in the neural retina from sham-operated control eyes with that in eyes during lens regeneration. An initial increase in 3H-uridine uptake was seen one to three days after lentectomy. This was followed by greater incorporation of 3H-leucine, indicating increased protein synthesis between 5 to 15 days after lens removal. A decrease in 3H-uridine uptake was also seen at 5 to 12 days after lentectomy. After 20 days both the RNA and protein synthesis returned to the normal level. Since the increase in protein synthesis is preceded by an increase in RNA synthesis, the two processes might be related. The results indicate significant changes in the synthesis of macromolecules by the neural retina following lentectomy. These may be indirectly related to the production of the neural retinal factor with stimulates lens differentiation.
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40
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Reyer RW. DNA replication in lens vesicles of Ambystoma maculatum embryos implanted into ocular or extra-ocular sites of host larvae. Exp Eye Res 1980; 31:451-62. [PMID: 7449880 DOI: 10.1016/s0014-4835(80)80029-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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41
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Brahma SK. Isofocusing and immunoelectrophoretic studies of soluble eye lens proteins from regenerated and normally developed Xenopus laevis. Exp Eye Res 1980; 30:269-75. [PMID: 6156856 DOI: 10.1016/0014-4835(80)90007-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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42
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chapter 11 Cellular Metaplasia or Transdifferentiaton as a Model for Retinal Cell Differentiation. Curr Top Dev Biol 1980. [DOI: 10.1016/s0070-2153(08)60162-3] [Citation(s) in RCA: 133] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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43
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Reyer RW. Repolarization of reversed, regenerating lenses in adult newts, Notophthalmus viridescens. Exp Eye Res 1977; 24:501-9. [PMID: 862682 DOI: 10.1016/0014-4835(77)90271-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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44
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Reyer RW. Morphological evidence for lens differentiation from intra-ocular implants of lens epithelium in Ambystoma maculatum. Exp Eye Res 1977; 24:511-22. [PMID: 862683 DOI: 10.1016/0014-4835(77)90272-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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