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Reddien PW. The purpose and ubiquity of turnover. Cell 2024; 187:2657-2681. [PMID: 38788689 DOI: 10.1016/j.cell.2024.04.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/19/2024] [Accepted: 04/24/2024] [Indexed: 05/26/2024]
Abstract
Turnover-constant component production and destruction-is ubiquitous in biology. Turnover occurs across organisms and scales, including for RNAs, proteins, membranes, macromolecular structures, organelles, cells, hair, feathers, nails, antlers, and teeth. For many systems, turnover might seem wasteful when degraded components are often fully functional. Some components turn over with shockingly high rates and others do not turn over at all, further making this process enigmatic. However, turnover can address fundamental problems by yielding powerful properties, including regeneration, rapid repair onset, clearance of unpredictable damage and errors, maintenance of low constitutive levels of disrepair, prevention of stable hazards, and transitions. I argue that trade-offs between turnover benefits and metabolic costs, combined with constraints on turnover, determine its presence and rates across distinct contexts. I suggest that the limits of turnover help explain aging and that turnover properties and the basis for its levels underlie this fundamental component of life.
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Affiliation(s)
- Peter W Reddien
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, MIT, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, MIT, Cambridge, MA 02139, USA.
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2
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Wang S, Sun Y, Liu X, Guo Y, Huang Y, Zhang S, Tian Q. Meis1 Controls the Differentiation of Eye Progenitor Cells and the Formation of Posterior Poles during Planarian Regeneration. Int J Mol Sci 2023; 24:ijms24043505. [PMID: 36834910 PMCID: PMC9961902 DOI: 10.3390/ijms24043505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/21/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023] Open
Abstract
As a member of TALE family, Meis1 has been proven to regulate cell proliferation and differentiation during cell fate commitment; however, the mechanism is still not fully understood. The planarian, which has an abundance of stem cells (neoblasts) responsible for regenerating any organ after injury, is an ideal model for studying the mechanisms of tissue identity determination. Here, we characterized a planarian homolog of Meis1 from the planarian Dugesia japonica. Importantly, we found that knockdown of DjMeis1 inhibits the differentiation of neoblasts into eye progenitor cells and results in an eyeless phenotype with normal central nervous system. Furthermore, we observed that DjMeis1 is required for the activation of Wnt signaling pathway by promoting the Djwnt1 expression during posterior regeneration. The silencing of DjMeis1 suppresses the expression of Djwnt1 and results in the inability to reconstruct posterior poles. In general, our findings indicated that DjMeis1 acts as a trigger for the activation of eye and tail regeneration by regulating the differentiation of eye progenitor cells and the formation of posterior poles, respectively.
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Affiliation(s)
- Shaocong Wang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Yujia Sun
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Xiaomai Liu
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Yajun Guo
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Yongding Huang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Shoutao Zhang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
- Longhu Laboratory of Advanced Immunology, Zhengzhou 450046, China
- Correspondence: (S.Z.); (Q.T.)
| | - Qingnan Tian
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
- Correspondence: (S.Z.); (Q.T.)
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Reddien PW. Principles of regeneration revealed by the planarian eye. Curr Opin Cell Biol 2021; 73:19-25. [PMID: 34134046 PMCID: PMC11064094 DOI: 10.1016/j.ceb.2021.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/06/2021] [Indexed: 02/07/2023]
Abstract
One approach to elucidating the principles of regeneration is to investigate mechanisms that regenerate a target organ. Planarian eyes are discrete, visible structures that are dispensable for viability, making them powerful for studying the logic of regeneration. Fate specification in eye regeneration occurs in stem cells (neoblasts), generating eye progenitors. Eye progenitor production is not responsive to the presence or absence of the eye, with regeneration explained by constant progenitor production in the appropriate positional environment. Eye progenitors display coarse spatial specification. A combination of eye-extrinsic cues and self-organization with differentiated eye cells dictate where migratory eye progenitors target. Finally, guidepost-like cells influence regenerating axons to facilitate the restoration of eye circuitry. These findings from the eye as a case study present a model that explains how regeneration can occur.
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Affiliation(s)
- Peter W Reddien
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA; Department of Biology, MIT, Cambridge, MA, 02139, USA; Howard Hughes Medical Institute, MIT, Cambridge, MA, 02139, USA.
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4
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Johnson AA, Shokhirev MN, Shoshitaishvili B. Revamping the evolutionary theories of aging. Ageing Res Rev 2019; 55:100947. [PMID: 31449890 DOI: 10.1016/j.arr.2019.100947] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 07/20/2019] [Accepted: 08/21/2019] [Indexed: 01/04/2023]
Abstract
Radical lifespan disparities exist in the animal kingdom. While the ocean quahog can survive for half a millennium, the mayfly survives for less than 48 h. The evolutionary theories of aging seek to explain why such stark longevity differences exist and why a deleterious process like aging evolved. The classical mutation accumulation, antagonistic pleiotropy, and disposable soma theories predict that increased extrinsic mortality should select for the evolution of shorter lifespans and vice versa. Most experimental and comparative field studies conform to this prediction. Indeed, animals with extreme longevity (e.g., Greenland shark, bowhead whale, giant tortoise, vestimentiferan tubeworms) typically experience minimal predation. However, data from guppies, nematodes, and computational models show that increased extrinsic mortality can sometimes lead to longer evolved lifespans. The existence of theoretically immortal animals that experience extrinsic mortality - like planarian flatworms, panther worms, and hydra - further challenges classical assumptions. Octopuses pose another puzzle by exhibiting short lifespans and an uncanny intelligence, the latter of which is often associated with longevity and reduced extrinsic mortality. The evolutionary response to extrinsic mortality is likely dependent on multiple interacting factors in the organism, population, and ecology, including food availability, population density, reproductive cost, age-mortality interactions, and the mortality source.
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Affiliation(s)
| | - Maxim N Shokhirev
- Razavi Newman Integrative Genomics and Bioinformatics Core, The Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Boris Shoshitaishvili
- Division of Literatures, Cultures, and Languages, Stanford University, Stanford, CA, United States
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Jones S, Osman S, Howl J. The planarian Schmidtea mediterranea as a model system for the discovery and characterization of cell-penetrating peptides and bioportides. Chem Biol Drug Des 2019; 93:1036-1049. [PMID: 30790457 DOI: 10.1111/cbdd.13483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 12/13/2018] [Accepted: 12/27/2018] [Indexed: 12/16/2022]
Abstract
The general utility of the planarian Schmidtea mediterranea, an organism with remarkable regenerative capacity, was investigated as a convenient three-dimensional model to analyse the import of cell-penetrating peptides (CPPs) and bioportides (bioactive CPPs) into complex tissues. The unpigmented planarian blastema, 3 days post head amputation, is a robust platform to assess the penetration of red-fluorescent CPPs into epithelial cells and deeper tissues. Three planarian proteins, Ovo, ZicA and Djeya, which collectively control head remodelling and eye regeneration following decapitation, are a convenient source of novel cationic CPP vectors. One example, Djeya1 (RKLAFRYRRIKELYNSYR), is a particularly efficient and seemingly inert CPP vector that could be further developed to assist the delivery of bioactive payloads across the plasma membrane of eukaryotic cells. Eye regeneration, following head amputation, was utilized in an effort to identify bioportides capable of influencing stem cell-dependent morphogenesis. These investigations identified the tetradecapeptide mastoparan (INLKALAALAKKIL) as a bioportide able to influence the gross morphology of head development. We conclude that, compared with cellular monolayers, the S. mediterranea system provides many advantages and will support the identification of bioportides able to selectively modify the biology of totipotent neoblasts and, presumably, other mammalian stem cell types.
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Affiliation(s)
- Sarah Jones
- Molecular Pharmacology Group, Research Institute in Healthcare Science, Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton, UK
| | - Shaimaa Osman
- Peptide Chemistry Department, National Research Centre, Cairo, Egypt
| | - John Howl
- Molecular Pharmacology Group, Research Institute in Healthcare Science, Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton, UK
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6
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Matsuo R, Takatori Y, Hamada S, Koyanagi M, Matsuo Y. Expression and light-dependent translocation of β-arrestin in the visual system of the terrestrial slug Limax valentianus. ACTA ACUST UNITED AC 2017; 220:3301-3314. [PMID: 28687596 DOI: 10.1242/jeb.162701] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 07/05/2017] [Indexed: 11/20/2022]
Abstract
Vertebrates, cephalopods and arthropods are equipped with eyes that have the highest spatiotemporal resolution among the animal phyla. In parallel, only animals in these three phyla have visual arrestin specialized for the termination of visual signaling triggered by opsin, in addition to ubiquitously expressed β-arrestin that serves in terminating general G protein-coupled receptor signaling. Indeed, visual arrestin in Drosophila and rodents translocates to the opsin-rich subcellular region in response to light to reduce the overall sensitivity of photoreceptors in an illuminated environment (i.e. light adaptation). We thus hypothesized that, during evolution, visual arrestin has taken over the role of β-arrestin in those animals with eyes of high spatiotemporal resolution. If this is true, it is expected that β-arrestin plays a role similar to visual arrestin in those animals with low-resolution eyes. In the present study, we focused on the terrestrial mollusk Limax valentianus, a species related to cephalopods but that has only β-arrestin, and generated antibodies against β-arrestin. We found that β-arrestin is highly expressed in photosensory neurons, and translocates into the microvilli of the rhabdomere within 30 min in response to short wavelength light (400 nm), to which the Limax eye exhibits a robust response. These observations suggest that β-arrestin functions in the visual system of those animals that do not have visual arrestin. We also exploited anti-β-arrestin antibody to visualize the optic nerve projecting to the brain, and demonstrated its usefulness for tracing a visual ascending pathway.
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Affiliation(s)
- Ryota Matsuo
- Department of Environmental Sciences, International College of Arts and Sciences, Fukuoka Women's University, Fukuoka 813-8529, Japan
| | - Yuka Takatori
- Department of Environmental Sciences, International College of Arts and Sciences, Fukuoka Women's University, Fukuoka 813-8529, Japan
| | - Shun Hamada
- Department of Nutrition and Health Sciences, International College of Arts and Sciences, Fukuoka Women's University, Fukuoka 813-8529, Japan
| | - Mitsumasa Koyanagi
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Yuko Matsuo
- Department of Environmental Sciences, International College of Arts and Sciences, Fukuoka Women's University, Fukuoka 813-8529, Japan
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Morton JM, Saad MA, Beane WS. Surgical Ablation Assay for Studying Eye Regeneration in Planarians. J Vis Exp 2017. [PMID: 28448039 DOI: 10.3791/55594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
In the study of adult stem cells and regenerative mechanisms, planarian flatworms are a staple in vivo model system. This is due in large part to their abundant pluripotent stem cell population and ability to regenerate all cell and tissue types after injuries that would be catastrophic for most animals. Recently, planarians have gained popularity as a model for eye regeneration. Their ability to regenerate the entire eye (comprised of two tissue types: pigment cells and photoreceptors) allows for the dissection of the mechanisms regulating visual system regeneration. Eye ablation has several advantages over other techniques (such as decapitation or hole punch) for examining eye-specific pathways and mechanisms, the most important of which is that regeneration is largely restricted to eye tissues alone. The purpose of this video article is to demonstrate how to reliably remove the planarian optic cup without disturbing the brain or surrounding tissues. The handling of worms and maintenance of an established colony is also described. This technique uses a 31 G, 5/16-inch insulin needle to surgically scoop out the optic cup of planarians immobilized on a cold plate. This method encompasses both single and double eye ablation, with eyes regenerating within 1-2 weeks, allowing for a wide range of applications. In particular, this ablation technique can be easily combined with pharmacological and genetic (RNA interference) screens for a better understanding of regenerative mechanisms and their evolution, eye stem cells and their maintenance, and phototaxic behavioral responses and their neurological basis.
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Affiliation(s)
- Jacob M Morton
- Department of Biological Sciences, Western Michigan University
| | - Marwa A Saad
- Department of Biological Sciences, Western Michigan University
| | - Wendy S Beane
- Department of Biological Sciences, Western Michigan University;
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Ross KG, Currie KW, Pearson BJ, Zayas RM. Nervous system development and regeneration in freshwater planarians. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017; 6. [DOI: 10.1002/wdev.266] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/10/2017] [Accepted: 01/20/2017] [Indexed: 01/22/2023]
Affiliation(s)
- Kelly G. Ross
- Department of Biology San Diego State University San Diego CA USA
| | - Ko W. Currie
- Program in Developmental and Stem Cell Biology The Hospital for Sick Children Toronto Canada
- Department of Molecular Genetics University of Toronto Toronto Canada
- Ontario Institute for Cancer Research Toronto Canada
| | - Bret J. Pearson
- Program in Developmental and Stem Cell Biology The Hospital for Sick Children Toronto Canada
- Department of Molecular Genetics University of Toronto Toronto Canada
- Ontario Institute for Cancer Research Toronto Canada
| | - Ricardo M. Zayas
- Department of Biology San Diego State University San Diego CA USA
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Johnson AA, Guziewicz KE, Lee CJ, Kalathur RC, Pulido JS, Marmorstein LY, Marmorstein AD. Bestrophin 1 and retinal disease. Prog Retin Eye Res 2017; 58:45-69. [PMID: 28153808 DOI: 10.1016/j.preteyeres.2017.01.006] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 01/23/2017] [Accepted: 01/25/2017] [Indexed: 12/18/2022]
Abstract
Mutations in the gene BEST1 are causally associated with as many as five clinically distinct retinal degenerative diseases, which are collectively referred to as the "bestrophinopathies". These five associated diseases are: Best vitelliform macular dystrophy, autosomal recessive bestrophinopathy, adult-onset vitelliform macular dystrophy, autosomal dominant vitreoretinochoroidopathy, and retinitis pigmentosa. The most common of these is Best vitelliform macular dystrophy. Bestrophin 1 (Best1), the protein encoded by the gene BEST1, has been the subject of a great deal of research since it was first identified nearly two decades ago. Today we know that Best1 functions as both a pentameric anion channel and a regulator of intracellular Ca2+ signaling. Best1 is an integral membrane protein which, within the eye, is uniquely expressed in the retinal pigment epithelium where it predominantly localizes to the basolateral plasma membrane. Within the brain, Best1 expression has been documented in both glial cells and astrocytes where it functions in both tonic GABA release and glutamate transport. The crystal structure of Best1 has revealed critical information about how Best1 functions as an ion channel and how Ca2+ regulates that function. Studies using animal models have led to critical insights into the physiological roles of Best1 and advances in stem cell technology have allowed for the development of patient-derived, "disease in a dish" models. In this article we review our knowledge of Best1 and discuss prospects for near-term clinical trials to test therapies for the bestrophinopathies, a currently incurable and untreatable set of diseases.
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Affiliation(s)
- Adiv A Johnson
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA; Nikon Instruments, Melville, NY, USA
| | - Karina E Guziewicz
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - C Justin Lee
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Ravi C Kalathur
- New York Structural Biology Center, New York Consortium on Membrane Protein Structure, New York, NY, USA
| | - Jose S Pulido
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA
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González-Martín-Moro J, Hernández-Verdejo JL, Jiménez-Gahete AE. Surprising characteristics of visual systems of invertebrates. ACTA ACUST UNITED AC 2016; 92:19-28. [PMID: 27422478 DOI: 10.1016/j.oftal.2016.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 05/23/2016] [Accepted: 05/26/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVE To communicate relevant and striking aspects about the visual system of some close invertebrates. MATERIAL AND METHODS Review of the related literature. RESULTS The capacity of snails to regenerate a complete eye, the benefit of the oval shape of the compound eye of many flying insects as a way of stabilising the image during flight, the potential advantages related to the extreme refractive error that characterises the ocelli of many insects, as well as the ability to detect polarised light as a navigation system, are some of the surprising capabilities present in the small invertebrate eyes that are described in this work. CONCLUSIONS The invertebrate eyes have capabilities and sensorial modalities that are not present in the human eye. The study of the eyes of these animals can help us to improve our understanding of our visual system, and inspire the development of optical devices.
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Affiliation(s)
- J González-Martín-Moro
- Departamento de Oftalmología, Hospital Universitario del Henares, Coslada, Madrid, España; Universidad Francisco de Vitoria, Madrid, España.
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