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Markitantova YV, Grigoryan EN. Cellular and Molecular Triggers of Retinal Regeneration in Amphibians. Life (Basel) 2023; 13:1981. [PMID: 37895363 PMCID: PMC10608152 DOI: 10.3390/life13101981] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 09/23/2023] [Accepted: 09/26/2023] [Indexed: 10/29/2023] Open
Abstract
Understanding the mechanisms triggering the initiation of retinal regeneration in amphibians may advance the quest for prevention and treatment options for degenerating human retina diseases. Natural retinal regeneration in amphibians requires two cell sources, namely retinal pigment epithelium (RPE) and ciliary marginal zone. The disruption of RPE interaction with photoreceptors through surgery or injury triggers local and systemic responses for retinal protection. In mammals, disease-induced damage to the retina results in the shutdown of the function, cellular or oxidative stress, pronounced immune response, cell death and retinal degeneration. In contrast to retinal pathology in mammals, regenerative responses in amphibians have taxon-specific features ensuring efficient regeneration. These include rapid hemostasis, the recruitment of cells and factors of endogenous defense systems, activities of the immature immune system, high cell viability, and the efficiency of the extracellular matrix, cytoskeleton, and cell surface remodeling. These reactions are controlled by specific signaling pathways, transcription factors, and the epigenome, which are insufficiently studied. This review provides a summary of the mechanisms initiating retinal regeneration in amphibians and reveals its features collectively directed at recruiting universal responses to trauma to activate the cell sources of retinal regeneration. This study of the integrated molecular network of these processes is a prospect for future research in demand biomedicine.
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Affiliation(s)
| | - Eleonora N. Grigoryan
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 119334 Moscow, Russia;
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2
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Grigoryan EN. Pigment Epithelia of the Eye: Cell-Type Conversion in Regeneration and Disease. Life (Basel) 2022; 12:life12030382. [PMID: 35330132 PMCID: PMC8955580 DOI: 10.3390/life12030382] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/28/2022] [Accepted: 03/03/2022] [Indexed: 12/17/2022] Open
Abstract
Pigment epithelial cells (PECs) of the retina (RPE), ciliary body, and iris (IPE) are capable of altering their phenotype. The main pathway of phenotypic switching of eye PECs in vertebrates and humans in vivo and/or in vitro is neural/retinal. Besides, cells of amphibian IPE give rise to the lens and its derivatives, while mammalian and human RPE can be converted along the mesenchymal pathway. The PECs’ capability of conversion in vivo underlies the lens and retinal regeneration in lower vertebrates and retinal diseases such as proliferative vitreoretinopathy and fibrosis in mammals and humans. The present review considers these processes studied in vitro and in vivo in animal models and in humans. The molecular basis of conversion strategies in PECs is elucidated. Being predetermined onto- and phylogenetically, it includes a species-specific molecular context, differential expression of transcription factors, signaling pathways, and epigenomic changes. The accumulated knowledge regarding the mechanisms of PECs phenotypic switching allows the development of approaches to specified conversion for many purposes: obtaining cells for transplantation, creating conditions to stimulate natural regeneration of the retina and the lens, blocking undesirable conversions associated with eye pathology, and finding molecular markers of pathology to be targets of therapy.
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Affiliation(s)
- Eleonora N Grigoryan
- Kol'tsov Institute of Developmental Biology, Russian Academy of Sciences, 119334 Moscow, Russia
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3
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Arenas Gómez CM, Echeverri K. Salamanders: The molecular basis of tissue regeneration and its relevance to human disease. Curr Top Dev Biol 2021; 145:235-275. [PMID: 34074531 PMCID: PMC8186737 DOI: 10.1016/bs.ctdb.2020.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Salamanders are recognized for their ability to regenerate a broad range of tissues. They have also have been used for hundreds of years for classical developmental biology studies because of their large accessible embryos. The range of tissues these animals can regenerate is fascinating, from full limbs to parts of the brain or heart, a potential that is missing in humans. Many promising research efforts are working to decipher the molecular blueprints shared across the organisms that naturally have the capacity to regenerate different tissues and organs. Salamanders are an excellent example of a vertebrate that can functionally regenerate a wide range of tissue types. In this review, we outline some of the significant insights that have been made that are aiding in understanding the cellular and molecular mechanisms of tissue regeneration in salamanders and discuss why salamanders are a worthy model in which to study regenerative biology and how this may benefit research fields like regenerative medicine to develop therapies for humans in the future.
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Affiliation(s)
- Claudia Marcela Arenas Gómez
- Marine Biological Laboratory, Eugene Bell Center for Regenerative Biology and Tissue Engineering, University of Chicago, Woods Hole, MA, United States
| | - Karen Echeverri
- Marine Biological Laboratory, Eugene Bell Center for Regenerative Biology and Tissue Engineering, University of Chicago, Woods Hole, MA, United States.
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Liu Z, Wang R, Lin H, Liu Y. Lens regeneration in humans: using regenerative potential for tissue repairing. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1544. [PMID: 33313289 PMCID: PMC7729322 DOI: 10.21037/atm-2019-rcs-03] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The crystalline lens is an important optic element in human eyes. It is transparent and biconvex, refracting light and accommodating to form a clear retinal image. The lens originates from the embryonic ectoderm. The epithelial cells at the lens equator proliferate, elongate and differentiate into highly aligned lens fiber cells, which are the structural basis for maintaining the transparency of the lens. Cataract refers to the opacity of the lens. Currently, the treatment of cataract is to remove the opaque lens and implant an intraocular lens (IOL). This strategy is inappropriate for children younger than 2 years, because a developing eyeball is prone to have severe complications such as inflammatory proliferation and secondary glaucoma. On the other hand, the absence of the crystalline lens greatly affects visual function rehabilitation. The researchers found that mammalian lenses possess regenerative potential. We identified lens stem cells through linear tracking experiments and designed a minimally invasive lens-content removal surgery (MILS) to remove the opaque lens material while preserving the lens capsule, stem cells and microenvironment. In infants with congenital cataract, functional lens regeneration in situ can be observed after MILS, and the prognosis of visual function is better than that of traditional surgery. Because of insufficient regenerative ability in humans, the morphology and volume of the regenerated lens cannot reach the level of a normal lens. The activation, proliferation and differentiation of lens stem cells and the alignment of lens fibers are regulated by epigenetic factors, growth factors, transcription factors, immune system and other signals and their interactions. The construction of appropriate microenvironment can accelerate lens regeneration and improve its morphology. The therapeutic concept of MILS combined with microenvironment manipulation to activate endogenous stem cells for functional regeneration of organs in situ can be extended to other tissues and organs with strong self-renewal and repair ability.
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Affiliation(s)
- Zhenzhen Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Ruixin Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Haotian Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yizhi Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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5
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Vergara MN, Tsissios G, Del Rio-Tsonis K. Lens regeneration: a historical perspective. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2019; 62:351-361. [PMID: 29877565 PMCID: PMC6378223 DOI: 10.1387/ijdb.180084nv] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The idea of regenerating injured body parts has captivated human imagination for centuries, and the topic still remains an area of extensive scientific research. This review focuses on the process of lens regeneration: its history, our current knowledge, and the questions that remain unanswered. By highlighting some of the milestones that have shaped our understanding of this phenomenon and the contributions of scientists who have dedicated their lives to investigating these questions, we explore how regeneration enquiry evolved into the science it is today, and how technological advances accelerated our understanding of these remarkable processes.
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Affiliation(s)
- M Natalia Vergara
- Department of Ophthalmology, University of Colorado Denver School of Medicine, Aurora, CO, USA
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6
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Bucan V, Peck CT, Nasser I, Liebsch C, Vogt PM, Strauß S. Identification of axolotl BH3-only proteins and expression in axolotl organs and apoptotic limb regeneration tissue. Biol Open 2018; 7:7/8/bio036293. [PMID: 30154109 PMCID: PMC6124574 DOI: 10.1242/bio.036293] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Like other urodela amphibians, axolotls are able to regenerate lost appendages, even as adults, rendering them unique among higher vertebrates. In reaction to the severe trauma of a lost limb, apoptosis seems to be primarily implicated in the removal of injured cells and tissue homeostasis. Little, however, is known about apoptotic pathways and control mechanisms. Therefore, here we provide additional information regarding the mechanisms of tissue degradation. Expression patterns of Bcl-2 family members were analyzed using reverse transcriptase-PCR, western blotting and immunofluorescence. In our study, we identified ten putative axolotl orthologs of the Bcl-2 family. We demonstrated that BH3-only proteins are differentially expressed in some axolotl organs, while they are expressed broadly in tail composite tissue and limb regeneration blastema. The importance of Bcl-2 family members is also indicated by detecting the expression of proapoptotic protein Bak in spatial congruence to apoptosis in the early stages of limb regeneration, while Bcl-2 expression was slightly modified. In conclusion, we demonstrate that Bcl-2 family members are conserved in the axolotl and might be involved in the tissue degradation processes that occur during limb regeneration. Summary: In our study we identified ten putative axolotl orthologs of the Bcl-2 family. We demonstrate that Bcl-2 family members are conserved in the axolotl and are involved in tissue degradation processes during limb regeneration.
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Affiliation(s)
- Vesna Bucan
- Department of Plastic, Aesthetic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Claas-Tido Peck
- Department of Plastic, Aesthetic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Inas Nasser
- Department of Plastic, Aesthetic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Christina Liebsch
- Department of Plastic, Aesthetic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Peter M Vogt
- Department of Plastic, Aesthetic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Sarah Strauß
- Department of Plastic, Aesthetic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
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7
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Wagner I, Wang H, Weissert PM, Straube WL, Shevchenko A, Gentzel M, Brito G, Tazaki A, Oliveira C, Sugiura T, Shevchenko A, Simon A, Drechsel DN, Tanaka EM. Serum Proteases Potentiate BMP-Induced Cell Cycle Re-entry of Dedifferentiating Muscle Cells during Newt Limb Regeneration. Dev Cell 2017; 40:608-617.e6. [PMID: 28350991 DOI: 10.1016/j.devcel.2017.03.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 12/23/2016] [Accepted: 02/27/2017] [Indexed: 12/28/2022]
Abstract
Limb amputation in the newt induces myofibers to dedifferentiate and re-enter the cell cycle to generate proliferative myogenic precursors in the regeneration blastema. Here we show that bone morphogenetic proteins (BMPs) and mature BMPs that have been further cleaved by serum proteases induce cell cycle entry by dedifferentiating newt muscle cells. Protease-activated BMP4/7 heterodimers that are present in serum strongly induced myotube cell cycle re-entry with protease cleavage yielding a 30-fold potency increase of BMP4/7 compared with canonical BMP4/7. Inhibition of BMP signaling via muscle-specific dominant-negative receptor expression reduced cell cycle entry in vitro and in vivo. In vivo inhibition of serine protease activity depressed cell cycle re-entry, which in turn was rescued by cleaved-mimic BMP. This work identifies a mechanism of BMP activation that generates blastema cells from differentiated muscle.
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Affiliation(s)
- Ines Wagner
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany; DFG Research Center for Regenerative Therapies, Technische Universität Dresden, Fetscherstrasse 105, 01307 Dresden, Germany
| | - Heng Wang
- Department of Cell and Molecular Biology, Centre of Developmental Biology for Regenerative Medicine, Karolinska Institute, Berzelius väg 35, 17177 Stockholm, Sweden
| | - Philipp M Weissert
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany; DFG Research Center for Regenerative Therapies, Technische Universität Dresden, Fetscherstrasse 105, 01307 Dresden, Germany
| | - Werner L Straube
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Anna Shevchenko
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Marc Gentzel
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Goncalo Brito
- Department of Cell and Molecular Biology, Centre of Developmental Biology for Regenerative Medicine, Karolinska Institute, Berzelius väg 35, 17177 Stockholm, Sweden
| | - Akira Tazaki
- DFG Research Center for Regenerative Therapies, Technische Universität Dresden, Fetscherstrasse 105, 01307 Dresden, Germany
| | - Catarina Oliveira
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany; DFG Research Center for Regenerative Therapies, Technische Universität Dresden, Fetscherstrasse 105, 01307 Dresden, Germany
| | - Takuji Sugiura
- DFG Research Center for Regenerative Therapies, Technische Universität Dresden, Fetscherstrasse 105, 01307 Dresden, Germany
| | - Andrej Shevchenko
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - András Simon
- Department of Cell and Molecular Biology, Centre of Developmental Biology for Regenerative Medicine, Karolinska Institute, Berzelius väg 35, 17177 Stockholm, Sweden.
| | - David N Drechsel
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
| | - Elly M Tanaka
- DFG Research Center for Regenerative Therapies, Technische Universität Dresden, Fetscherstrasse 105, 01307 Dresden, Germany.
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8
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Godwin JW, Rosenthal N. Scar-free wound healing and regeneration in amphibians: immunological influences on regenerative success. Differentiation 2014; 87:66-75. [PMID: 24565918 DOI: 10.1016/j.diff.2014.02.002] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 02/02/2014] [Accepted: 02/04/2014] [Indexed: 12/17/2022]
Abstract
Salamanders and frogs are distinct orders of Amphibians with very different immune systems during adult life, exhibiting varying potential for scar free repair and regeneration. While salamanders can regenerate a range of body parts throughout all stages of life, regeneration is restricted to early stages of frog development. Comparison of these two closely related amphibian orders provides insights into the immunological influences on wound repair, and the different strategies that have evolved either to limit infection or to facilitate efficient regeneration. After injury, cells of the immune system are responsible for the removal of damaged cells and providing a cohort of important growth factors and signaling molecules. Immune cells not only regulate new vessel growth important for supplying essential nutrients to damaged tissue but, modulate the extracellular matrix environment by regulating fibroblasts and the scarring response. The profile of immune cell infiltration and their interaction with local tissue immune cells directly influences many aspects of the wound healing outcomes and can facilitate or prevent regeneration. Evidence is emerging that the transition from wound healing to regeneration is reliant on immune cell engagement and that the success of regeneration in amphibians may depend on complex interactions between stem cell progenitors and immune cell subsets. The potential immunological barriers to mammalian regeneration are discussed with implications for the successful delivery of stem cell therapeutic strategies in patients.
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Affiliation(s)
- James W Godwin
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Nadia Rosenthal
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia; National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
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9
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Sousounis K, Looso M, Maki N, Ivester CJ, Braun T, Tsonis PA. Transcriptome analysis of newt lens regeneration reveals distinct gradients in gene expression patterns. PLoS One 2013; 8:e61445. [PMID: 23613853 PMCID: PMC3628982 DOI: 10.1371/journal.pone.0061445] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/09/2013] [Indexed: 12/11/2022] Open
Abstract
Regeneration of the lens in newts is quite a unique process. The lens is removed in its entirety and regeneration ensues from the pigment epithelial cells of the dorsal iris via transdifferentiation. The same type of cells from the ventral iris are not capable of regenerating a lens. It is, thus, expected that differences between dorsal and ventral iris during the process of regeneration might provide important clues pertaining to the mechanism of regeneration. In this paper, we employed next generation RNA-seq to determine gene expression patterns during lens regeneration in Notophthalmus viridescens. The expression of more than 38,000 transcripts was compared between dorsal and ventral iris. Although very few genes were found to be dorsal- or ventral-specific, certain groups of genes were up-regulated specifically in the dorsal iris. These genes are involved in cell cycle, gene regulation, cytoskeleton and immune response. In addition, the expression of six highly regulated genes, TBX5, FGF10, UNC5B, VAX2, NR2F5, and NTN1, was verified using qRT-PCR. These graded gene expression patterns provide insight into the mechanism of lens regeneration, the markers that are specific to dorsal or ventral iris, and layout a map for future studies in the field.
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Affiliation(s)
- Konstantinos Sousounis
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
| | - Mario Looso
- Department of Bioinformatics, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Nobuyasu Maki
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
| | - Clifford J. Ivester
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
| | - Thomas Braun
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
- * E-mail: (TB); (PAT)
| | - Panagiotis A. Tsonis
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
- * E-mail: (TB); (PAT)
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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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Abstract
Comparative studies of lens and retina regeneration have been conducted within a wide variety of animals over the last 100 years. Although amphibians, fish, birds and mammals have all been noted to possess lens- or retina-regenerative properties at specific developmental stages, lens or retina regeneration in adult animals is limited to lower vertebrates. The present review covers the newest perspectives on lens and retina regeneration from these different model organisms with a focus on future trends in regeneration research.
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12
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Regeneration and reprogramming. Curr Opin Genet Dev 2012; 22:485-93. [PMID: 23084810 DOI: 10.1016/j.gde.2012.09.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 08/24/2012] [Accepted: 09/17/2012] [Indexed: 01/14/2023]
Abstract
Recent reprogramming studies indicate that mammalian, somatic cells have the potential to achieve pluripotent states and undergo cell type switching. Such cellular traits are observed under natural conditions in animals that regenerate complex organs. A number of invertebrates display the amazing trait of whole body regeneration. Underlying this trait is the maintenance of pluripotent cells in somatic tissue, and molecular studies indicate the use of common players associated with pluripotency and germ cell properties between these invertebrates and mammalian pluripotent cells. In regenerative vertebrates, heart regeneration, lens regeneration, and retinal regeneration provide good examples of dedifferentiation and transdifferentiation. The molecular factors associated with these phenomena are discussed.
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King MW, Neff AW, Mescher AL. The developing Xenopus limb as a model for studies on the balance between inflammation and regeneration. Anat Rec (Hoboken) 2012; 295:1552-61. [PMID: 22933418 DOI: 10.1002/ar.22443] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 12/16/2011] [Indexed: 01/21/2023]
Abstract
The roles of inflammation and immune cell reactivity triggered by amputation have only recently begun to be addressed in investigations of epimorphic regeneration, although studies of tissue repair in mammals clearly show the importance of the immune system in determining the quality of the repair process. Here, we first review inflammation-related work in non-mammalian systems of epimorphic regeneration which suggests that regeneration of an amputated appendage requires continuous modulation of the local immune response, from the first hours after amputation through the period of blastema patterning. We then present data on the effects of anti-inflammatory and proinflammatory agents on regeneration of larval Xenopus hindlimbs. Treatment with the glucocorticoid beclomethasone immediately after amputation inhibits regeneration in regeneration-complete stage 53 limbs. Other anti-inflammatory agents, including the inhibitors of cyclooxygenase-2 (COX-2) activity celecoxib and diclofenac, applied similarly to larvae amputated at stage 55, when the capacity for limb regeneration is normally being lost, restore regenerative capacity. This suggests that although injury-related events sensitive to glucocorticoids are necessary for regeneration, resolution of the inflammatory response may also be required to allow the complete regenerative response and normal blastema patterning. Conversely, if resolution of inflammation is prevented by local treatment of amputated limbs with beryllium, a strong immunoadjuvant, regeneration is inhibited, and gene expression data suggest that this inhibition results from a failure of normal blastema patterning. Both positive and negative effects of immune- or inflammation-related activities occur during anuran limb regeneration and this underscores the importance of considering immune cells in studies of epimorphic regeneration.
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Affiliation(s)
- Michael W King
- Indiana University Center for Regenerative Biology and Medicine, Indiana University School of Medicine, Terre Haute, Indiana, USA
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Neff AW, King MW, Mescher AL. Dedifferentiation and the role of sall4 in reprogramming and patterning during amphibian limb regeneration. Dev Dyn 2011; 240:979-89. [DOI: 10.1002/dvdy.22554] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2010] [Indexed: 01/12/2023] Open
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