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Mukundan N, Hariharan N, Sasidharan V, Lakshmanan V, Palakodeti D, Jamora C. Poly (A) binding protein 2 is critical for stem cell differentiation during regeneration in the planarian Schmidtea mediterranea. Front Cell Dev Biol 2024; 12:1433142. [PMID: 39376632 PMCID: PMC11456742 DOI: 10.3389/fcell.2024.1433142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Accepted: 08/21/2024] [Indexed: 10/09/2024] Open
Abstract
Post-transcriptional regulation has emerged as a key mechanism for regulating stem cell renewal and differentiation, which is essential for understanding tissue regeneration and homeostasis. Poly(A)-binding proteins are a family of RNA-binding proteins that play a vital role in post-transcriptional regulation by controlling mRNA stability and protein synthesis. The involvement of poly(A) binding proteins in a wide range of cellular functions is increasingly being investigated. In this study, we used the regenerative model planarian organism Schmidtea mediterranea to demonstrate the critical role of poly(A)-binding protein 2 (PABP2) in regulating neoblast maintenance and differentiation. A deficit in PABP2 blocks the transition of neoblasts toward immediate early progenitors, leading to an enhanced pool of non-committed neoblasts and a decreased progenitor population. This is reflected in variations in the transcriptome profile, providing evidence of downregulation in multiple lineages. Thus, an insufficiency of PABP2 resulted in defective formation and organization of tissue, leading to abnormal regeneration. Our study reveals the essential role of PABP2 in regulating genes that mediate stem cell commitment to early progenitors during tissue regeneration.
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Affiliation(s)
- Namita Mukundan
- Integrative Chemical Biology (ICB), Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
- Manipal Academy of Higher Education, Manipal, India
| | - Nivedita Hariharan
- Integrative Chemical Biology (ICB), Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
| | | | - Vairavan Lakshmanan
- Integrative Chemical Biology (ICB), Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
| | - Dasaradhi Palakodeti
- Integrative Chemical Biology (ICB), Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
- Manipal Academy of Higher Education, Manipal, India
| | - Colin Jamora
- Integrative Chemical Biology (ICB), Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
- Department of Life Science, Shiv Nadar Institution of Eminence, Greater Noida, Uttar Pradesh, India
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2
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Lee JR, Boothe T, Mauksch C, Thommen A, Rink JC. Epidermal turnover in the planarian Schmidtea mediterranea involves basal cell extrusion and intestinal digestion. Cell Rep 2024; 43:114305. [PMID: 38906148 DOI: 10.1016/j.celrep.2024.114305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 03/21/2024] [Accepted: 05/15/2024] [Indexed: 06/23/2024] Open
Abstract
Planarian flatworms undergo continuous internal turnover, wherein old cells are replaced by the division progeny of adult pluripotent stem cells (neoblasts). How cell turnover is carried out at the organismal level remains an intriguing question in planarians and other systems. While previous studies have predominantly focused on neoblast proliferation, little is known about the processes that mediate cell loss during tissue homeostasis. Here, we use the planarian epidermis as a model to study the mechanisms of cell removal. We established a covalent dye-labeling assay and image analysis pipeline to quantify the cell turnover rate in the planarian epidermis. Our findings indicate that the ventral epidermis is highly dynamic and epidermal cells undergo internalization via basal extrusion, followed by a relocation toward the intestine and ultimately digestion by intestinal phagocytes. Overall, our study reveals a complex homeostatic process of cell clearance that may generally allow planarians to catabolize their own cells.
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Affiliation(s)
- Jun-Ru Lee
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany; Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany
| | - Tobias Boothe
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Clemens Mauksch
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Albert Thommen
- Cancer Metabolism Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Jochen C Rink
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany; Faculty of Biology and Psychology, Georg-August-University, Göttingen, Germany.
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3
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Avalos PN, Wong LL, Forsthoefel DJ. Extracellular vesicles promote proliferation in an animal model of regeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.22.586206. [PMID: 38712279 PMCID: PMC11071309 DOI: 10.1101/2024.03.22.586206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Extracellular vesicles (EVs) are secreted nanoparticles composed of a lipid bilayer that carry lipid, protein, and nucleic acid cargo between cells as a mode of intercellular communication. Although EVs can promote tissue repair in mammals, their roles in animals with greater regenerative capacity are not well understood. Planarian flatworms are capable of whole body regeneration due to pluripotent somatic stem cells called neoblasts that proliferate in response to injury. Here, using transmission electron microscopy, nanoparticle tracking analysis, and protein content examination, we showed that EVs enriched from the tissues of the planarian Schmidtea mediterranea had similar morphology and size as other eukaryotic EVs, and that these EVs carried orthologs of the conserved EV biogenesis regulators ALIX and TSG101. PKH67-labeled EVs were taken up more quickly by S/G2 neoblasts than G1 neoblasts/early progeny and differentiated cells. When injected into living planarians, EVs from regenerating tissue fragments enhanced upregulation of neoblast-associated transcripts. In addition, EV injection increased the number of F-ara-EdU-labelled cells by 49% as compared to buffer injection only. Our findings demonstrate that regenerating planarians produce EVs that promote stem cell proliferation, and suggest the planarian as an amenable in vivo model for the study of EV function during regeneration.
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Affiliation(s)
- Priscilla N. Avalos
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Lily L. Wong
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - David J. Forsthoefel
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
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4
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Herz M, Zarowiecki M, Wessels L, Pätzel K, Herrmann R, Braun C, Holroyd N, Huckvale T, Bergmann M, Spiliotis M, Koziol U, Berriman M, Brehm K. Genome-wide transcriptome analysis of Echinococcus multilocularis larvae and germinative cell cultures reveals genes involved in parasite stem cell function. Front Cell Infect Microbiol 2024; 14:1335946. [PMID: 38333034 PMCID: PMC10850878 DOI: 10.3389/fcimb.2024.1335946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/12/2024] [Indexed: 02/10/2024] Open
Abstract
The lethal zoonosis alveolar echinococcosis is caused by tumour-like growth of the metacestode stage of the tapeworm Echinococcus multilocularis within host organs. We previously demonstrated that metacestode proliferation is exclusively driven by somatic stem cells (germinative cells), which are the only mitotically active parasite cells that give rise to all differentiated cell types. The Echinococcus gene repertoire required for germinative cell maintenance and differentiation has not been characterised so far. We herein carried out Illumina sequencing on cDNA from Echinococcus metacestode vesicles, from metacestode tissue depleted of germinative cells, and from Echinococcus primary cell cultures. We identified a set of ~1,180 genes associated with germinative cells, which contained numerous known stem cell markers alongside genes involved in replication, cell cycle regulation, mitosis, meiosis, epigenetic modification, and nucleotide metabolism. Interestingly, we also identified 44 stem cell associated transcription factors that are likely involved in regulating germinative cell differentiation and/or pluripotency. By in situ hybridization and pulse-chase experiments, we also found a new general Echinococcus stem cell marker, EmCIP2Ah, and we provide evidence implying the presence of a slow cycling stem cell sub-population expressing the extracellular matrix factor Emkal1. RNA-Seq analyses on primary cell cultures revealed that metacestode-derived Echinococcus stem cells display an expanded differentiation capability and do not only form differentiated cell types of the metacestode, but also cells expressing genes specific for protoscoleces, adult worms, and oncospheres, including an ortholog of the schistosome praziquantel target, EmTRPMPZQ. Finally, we show that primary cell cultures contain a cell population expressing an ortholog of the tumour necrosis factor α receptor family and that mammalian TNFα accelerates the development of metacestode vesicles from germinative cells. Taken together, our analyses provide a robust and comprehensive characterization of the Echinococcus germinative cell transcriptome, demonstrate expanded differentiation capability of metacestode derived stem cells, and underscore the potential of primary germinative cell cultures to investigate developmental processes of the parasite. These data are relevant for studies into the role of Echinococcus stem cells in parasite development and will facilitate the design of anti-parasitic drugs that specifically act on the parasite germinative cell compartment.
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Affiliation(s)
- Michaela Herz
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | | | - Leonie Wessels
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Katharina Pätzel
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Ruth Herrmann
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Christiane Braun
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Nancy Holroyd
- Parasite Genomics, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Thomas Huckvale
- Parasite Genomics, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Monika Bergmann
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Markus Spiliotis
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Uriel Koziol
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Matthew Berriman
- Parasite Genomics, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Klaus Brehm
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
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Wang KT, Tapper J, Adler CE. Purification of Planarian Stem Cells Using a Draq5-Based FACS Approach. Methods Mol Biol 2024; 2805:203-212. [PMID: 39008184 DOI: 10.1007/978-1-0716-3854-5_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Planarians are flatworms that have the remarkable ability to regenerate entirely new animals. This regenerative ability requires abundant adult stem cells called neoblasts, which are relatively small in size, sensitive to irradiation and the only proliferative cells in the animal. Despite the lack of cell surface markers, fluorescence-activated cell sorting (FACS) protocols have been developed to discriminate and isolate neoblasts, based on DNA content. Here, we describe a protocol that combines staining of far-red DNA dye Draq5, Calcein-AM and DAPI, along with a shortened processing time. This profiling strategy can be used to functionally characterize the neoblast population in pharmacologically-treated or gene knockdown animals. Highly purified neoblasts can be analyzed with downstream assays, such as in situ hybridization and RNA sequencing.
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Affiliation(s)
- Kuang-Tse Wang
- Department of Molecular Medicine, Cornell University, College of Veterinary Medicine, Ithaca, NY, USA
| | - Justin Tapper
- Department of Molecular Medicine, Cornell University, College of Veterinary Medicine, Ithaca, NY, USA
| | - Carolyn E Adler
- Department of Molecular Medicine, Cornell University, College of Veterinary Medicine, Ithaca, NY, USA.
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Kuroki Y, Agata K. Isolation of planarian viable cells using fluorescence-activated cell sorting for advancing single-cell transcriptome analysis. Genes Cells 2023; 28:800-810. [PMID: 37723830 PMCID: PMC11448005 DOI: 10.1111/gtc.13068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/20/2023]
Abstract
Preparing viable single cells is critical for conducting single-cell RNA sequencing (scRNA-seq) because the presence of ambient RNA from dead or damaged cells can interfere with data analysis. Here, we developed a method for isolating viable single cells from adult planarian bodies using fluorescence-activated cell sorting (FACS). This method was then applied to both adult pluripotent stem cells (aPSCs) and differentiating/differentiated cells. Initially, we employed a violet instead of ultraviolet (UV) laser to excite Hoechst 33342 to reduce cellular damage. After optimization of cell staining conditions and FACS compensation, we generated FACS profiles similar to those created using a previous method that employed a UV laser. Despite successfully obtaining high-quality RNA sequencing data for aPSCs, non-aPSCs produced low-quality RNA reads (i.e., <60% of cells possessing barcoding mRNAs). Subsequently, we identified an effective FACS gating condition that excluded low-quality cells and tissue debris without staining. This non-staining isolation strategy not only reduced post-dissociation time but also enabled high-quality scRNA-seq results for all cell types (i.e., >80%). Taken together, these findings imply that the non-staining FACS strategy may be beneficial for isolating viable cells not only from planarians but also from other organisms and tissues for scRNA-seq studies.
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Affiliation(s)
- Yoshihito Kuroki
- Laboratory of Regeneration Biology, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, The Graduate University for Advanced Studies, SOKENDAI, Okazaki, Japan
| | - Kiyokazu Agata
- Laboratory of Regeneration Biology, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, The Graduate University for Advanced Studies, SOKENDAI, Okazaki, Japan
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Wiggans M, Zhu SJ, Molinaro AM, Pearson BJ. The BAF chromatin remodeling complex licenses planarian stem cells access to ectodermal and mesodermal cell fates. BMC Biol 2023; 21:227. [PMID: 37864247 PMCID: PMC10589948 DOI: 10.1186/s12915-023-01730-y] [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: 02/09/2023] [Accepted: 10/10/2023] [Indexed: 10/22/2023] Open
Abstract
BACKGROUND The flatworm planarian, Schmidtea mediterranea, has a large population of adult stem cells (ASCs) that replace any cell type during tissue turnover or regeneration. How planarian ASCs (called neoblasts) manage self-renewal with the ability to produce daughter cells of different cell lineages (multipotency) is not well understood. Chromatin remodeling complexes ultimately control access to DNA regions of chromosomes and together with specific transcription factors determine whether a gene is transcribed in a given cell type. Previous work in planarians determined that RNAi of core components of the BAF chromatin remodeling complex, brg1 and smarcc2, caused increased ASCs and failed regeneration, but how these cellular defects arise at the level of gene regulation in neoblasts is unknown. RESULTS Here, we perform ATAC and RNA sequencing on purified neoblasts, deficient for the BAF complex subunits brg-1 and smarcc2. The data demonstrate that the BAF complex promotes chromatin accessibility and facilitates transcription at target loci, as in other systems. Interestingly, we find that the BAF complex enables access to genes known to be required for the generation of mesoderm- and ectoderm-derived lineages, including muscle, parenchymal cathepsin, neural, and epithelial lineages. BAF complex knockdowns result in disrupted differentiation into these cell lineages and functional consequences on planarian regeneration and tissue turnover. Notably, we did not detect a role for the BAF complex in neoblasts making endodermal lineages. CONCLUSIONS Our study provides functional insights into how the BAF complex contributes to cell fate decisions in planarian ASCs in vivo.
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Affiliation(s)
- Mallory Wiggans
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, M5G0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S1A8, Canada
| | - Shu Jun Zhu
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, M5G0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S1A8, Canada
| | - Alyssa M Molinaro
- Present address: Oregon Health & Science University, Portland, OR, 97239, USA
| | - Bret J Pearson
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, M5G0A4, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S1A8, Canada.
- Present address: Oregon Health & Science University, Portland, OR, 97239, USA.
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8
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Akheralie Z, Scidmore TJ, Pearson BJ. aristaless-like homeobox-3 is wound induced and promotes a low-Wnt environment required for planarian head regeneration. Development 2023; 150:dev201777. [PMID: 37681295 PMCID: PMC10560571 DOI: 10.1242/dev.201777] [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: 03/13/2023] [Accepted: 08/30/2023] [Indexed: 09/09/2023]
Abstract
The planarian Schmidtea mediterranea is a well-established model of adult regeneration, which is dependent on a large population of adult stem cells called neoblasts. Upon amputation, planarians undergo transcriptional wounding programs and coordinated stem cell proliferation to give rise to missing tissues. Interestingly, the Wnt signaling pathway is key to guiding what tissues are regenerated, yet less known are the transcriptional regulators that ensure proper activation and timing of signaling pathway components. Here, we have identified an aristaless-like homeobox transcription factor, alx-3, that is enriched in a population of putative neural-fated progenitor cells at homeostasis, and is also upregulated in stem cells and muscle cells at anterior-facing wounds upon amputation. Knockdown of alx-3 results in failure of head regeneration and patterning defects in amputated tail fragments. alx-3 is required for the expression of several early wound-induced genes, including the Wnt inhibitor notum, which is required to establish anterior polarity during regeneration. Together, these findings reveal a role for alx-3 as an early wound-response transcriptional regulator in both muscle cells and stem cells that is required for anterior regeneration by promoting a low-Wnt environment.
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Affiliation(s)
- Zaleena Akheralie
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G0A4, Canada
- University of Toronto, Department of Molecular Genetics, Toronto, ON M5S1A8, Canada
| | - Tanner J. Scidmore
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G0A4, Canada
- University of Toronto, Department of Molecular Genetics, Toronto, ON M5S1A8, Canada
| | - Bret J. Pearson
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G0A4, Canada
- University of Toronto, Department of Molecular Genetics, Toronto, ON M5S1A8, Canada
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Zhen H, Huang M, Zheng M, Gao L, Guo Z, Pang Q, Jin G, Zhou Z. WTAP regulates stem cells via TRAF6 to maintain planarian homeostasis and regeneration. Int J Biol Macromol 2023:124932. [PMID: 37268082 DOI: 10.1016/j.ijbiomac.2023.124932] [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: 12/12/2022] [Revised: 04/23/2023] [Accepted: 05/06/2023] [Indexed: 06/04/2023]
Abstract
WTAP, a highly conserved Wilms' tumor 1 interacting protein, is involved in a variety of biological processes. However, functional studies of WTAP in planarians have not been reported. In this study, we examined the spatiotemporal expression pattern of planarian DjWTAP and investigated its functions in planarians regeneration and homeostasis. Knocking-down DjWTAP resulted in severe morphological defects leading to lethality within 20 days. Silencing DjWTAP promoted the proliferation of PiwiA+ cells but impaired the lineage differentiation of epidermal, neural, digestive, and excretory cell types, suggesting a critical role for DjWTAP in stem cell self-renewal and differentiation in planarian. To further investigate the mechanisms underlying the defective differentiation, RNA-seq was employed to determine the transcriptomic alterations upon DjWTAP RNA interference. Histone 4 (H4), Histone-lysine N-methyltransferase-SETMAR like, and TNF receptor-associated factor 6 (TRAF6), were significantly upregulated in response to DjWTAP RNAi. Knocking-down TRAF6 largely rescued the defective tissue homeostasis and regeneration resulted from DjWTAP knockdown in planarians, suggesting that DjWTAP maintains planarian regeneration and homeostasis via TRAF6.
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Affiliation(s)
- Hui Zhen
- Guangdong Cardiovascular Institute, Medical Research Center, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Mujie Huang
- Guangdong Cardiovascular Institute, Medical Research Center, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Mingyue Zheng
- Guangdong Cardiovascular Institute, Medical Research Center, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Lili Gao
- Laboratory of Developmental and Evolutionary Biology, Shandong University of Technology, Zibo, China
| | - Zepeng Guo
- Guangdong Cardiovascular Institute, Medical Research Center, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Qiuxiang Pang
- Laboratory of Developmental and Evolutionary Biology, Shandong University of Technology, Zibo, China.
| | - Guoxiang Jin
- Guangdong Cardiovascular Institute, Medical Research Center, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China; Guangdong Provincial Geriatrics Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, China.
| | - Zhongjun Zhou
- Guangdong Cardiovascular Institute, Medical Research Center, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China; School of Biomedical Sciences, The University of Hong Kong, Hong Kong; Reproductive Medicine Center, The University of Hong Kong-Shenzhen Hospital, Shenzhen, CHINA.
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10
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Sun J, Shao X, Huang J, Gong M, Zhang J, Yuan Z. Multiple toxicity evaluations of perfluorooctane sulfonate on intact planarian Dugesia japonica. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:60932-60945. [PMID: 37042918 DOI: 10.1007/s11356-023-26842-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 04/03/2023] [Indexed: 05/10/2023]
Abstract
Perfluorooctane sulfonate (PFOS) is gaining widespread attention as a persistent organic pollutant with multiple mechanisms of toxicity. In this study, PFOS at different concentrations and different exposure times was used to evaluate the multiple toxicities on intact planarian Dugesia japonica. The proliferation of neoblasts, apoptosis, DNA damage and the expression levels of neuronal genes and the major genes of the Wnt pathway were effectively studied. The results demonstrated that the balance between proliferation and apoptosis of intact planarian cells was disrupted after PFOS exposure, which in turn affected tissue homeostasis and differentiation. PFOS exposure led to increased DNA damage and altered neuronal gene expression. In addition, PFOS exposure could down-regulate the expression of Wnt pathway genes, but the inhibition of the Wnt pathway by PFOS was time- and concentration-dependent. These findings suggest that PFOS has multiple toxic effects on planarians and may interfere with cell proliferation and neurodevelopment by affecting the key gene expression in the Wnt pathway, providing estimable information on the neurodevelopmental toxicity and ecotoxicity of PFOS toxicity in aquatic animals and environments.
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Affiliation(s)
- Jingyi Sun
- School of Life Sciences and Medicine, Shandong University of Technology, Zibo, 255000, Shandong, China
| | - Xinxin Shao
- School of Life Sciences and Medicine, Shandong University of Technology, Zibo, 255000, Shandong, China
| | - Jinying Huang
- School of Life Sciences and Medicine, Shandong University of Technology, Zibo, 255000, Shandong, China
| | - Mengxin Gong
- School of Life Sciences and Medicine, Shandong University of Technology, Zibo, 255000, Shandong, China
| | - Jianyong Zhang
- School of Life Sciences and Medicine, Shandong University of Technology, Zibo, 255000, Shandong, China
| | - Zuoqing Yuan
- School of Life Sciences and Medicine, Shandong University of Technology, Zibo, 255000, Shandong, China.
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11
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Planarians to schistosomes: an overview of flatworm cell-types and regulators. J Helminthol 2023; 97:e7. [PMID: 36644809 DOI: 10.1017/s0022149x22000621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Schistosomiasis remains a major neglected tropical disease that afflicts over 200 million people globally. Schistosomes, the aetiological agent of schistosomiasis, are parasitic flatworms that propagate between molluscan and mammalian hosts. Inside the mammalian host, schistosomes rapidly grow over 100-fold in size and develop into a sexually mature male or female that thrives in the bloodstream for several decades. Recent work has identified schistosome stem cells as the source that drives parasite transmission, reproduction and longevity. Moreover, studies have begun to uncover molecular programmes deployed by stem cells that are essential for tissue development and maintenance, parasite survival and immune evasion. Such programmes are reminiscent of neoblast-driven development and regeneration of planarians, the free-living flatworm relative of schistosomes. Over the last few decades, research in planarians has employed modern functional genomic tools that significantly enhanced our understanding of stem cell-driven animal development and regeneration. In this review, we take a broad stroke overview of major flatworm organ systems at the cellular and molecular levels. We summarize recent advances on genetic regulators that play critical roles in differentiation and maintenance of flatworm cell types. Finally, we provide perspectives on how investigation of basic parasite biology is critical to discovering new approaches to battle schistosomiasis.
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12
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Lindsay-Mosher N, Molinaro AM, Pearson BJ. An RNA/DNA-Based Flow Cytometry Approach for Isolating Slow-Cycling Stem Cells. Methods Mol Biol 2023; 2680:157-168. [PMID: 37428376 DOI: 10.1007/978-1-0716-3275-8_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Flow cytometry methods for sorting specific populations of cells based on fluorescence or physical properties have been a widely used technique for decades. Flow cytometry has been particularly vital to the study of planarians, which remain refractory to transgenic transformation, as it has provided a work-around solution for studying stem cell biology and lineage relationships in the context of regeneration. Many flow cytometry applications have been published in planarians, beginning with broad Hoechst-based strategies for isolating cycling stem cells and progressing to more function-based approaches involving vital dyes and surface antibodies. In this protocol, we look to build on the classic DNA-labeling Hoechst staining strategy by adding pyronin Y staining to label RNA. While Hoechst labeling alone allows for the isolation of stem cells in the S/G2/M phases of the cell cycle, heterogeneity within the population of stem cells with 2 C DNA content is not resolved. By considering RNA levels, this protocol can further divide this population of stem cells into two groups: G1 stem cells with relatively high RNA content and a slow-cycling population with low RNA content, which we call RNAlow stem cells. In addition, we provide instruction for combining this RNA/DNA flow cytometry protocol with EdU labeling experiments and describe an optional step for incorporating immunostaining prior to cell sorting (in this case with the pluripotency marker TSPAN-1). This protocol adds a new staining strategy and examples of combinatorial flow cytometry approaches to the repertoire of flow cytometry techniques for studying planarian stem cells.
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Affiliation(s)
- Nicole Lindsay-Mosher
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, Canada
| | - Alyssa M Molinaro
- Pape Research Institute, Oregon Health & Science University, Portland, OR, USA
| | - Bret J Pearson
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, Canada.
- Pape Research Institute, Oregon Health & Science University, Portland, OR, USA.
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13
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Hoffman M, Wurtzel O. PLANAtools-An interactive gene expression repository for the planarian Schmidtea mediterranea. Front Cell Dev Biol 2023; 11:1149537. [PMID: 37035247 PMCID: PMC10076545 DOI: 10.3389/fcell.2023.1149537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 03/16/2023] [Indexed: 04/11/2023] Open
Affiliation(s)
- Michael Hoffman
- The George S. Wise Faculty of Life Sciences, School of Neurobiology, Biochemistry, and Biophysics, Tel Aviv University, Tel Aviv, Israel
| | - Omri Wurtzel
- The George S. Wise Faculty of Life Sciences, School of Neurobiology, Biochemistry, and Biophysics, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- *Correspondence: Omri Wurtzel,
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14
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Dagan Y, Yesharim Y, Bonneau AR, Frankovits T, Schwartz S, Reddien PW, Wurtzel O. m6A is required for resolving progenitor identity during planarian stem cell differentiation. EMBO J 2022; 41:e109895. [PMID: 35971838 PMCID: PMC9627665 DOI: 10.15252/embj.2021109895] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 12/13/2022] Open
Abstract
Regeneration and tissue homeostasis require accurate production of missing cell lineages. Cell production is driven by changes to gene expression, which is shaped by multiple layers of regulation. Here, we find that the ubiquitous mRNA base-modification, m6A, is required for proper cell fate choice and cellular maturation in planarian stem cells (neoblasts). We mapped m6A-enriched regions in 7,600 planarian genes and found that perturbation of the m6A pathway resulted in progressive deterioration of tissues and death. Using single-cell RNA sequencing of >20,000 cells following perturbation of the m6A pathway, we identified an increase in expression of noncanonical histone variants, and that inhibition of the pathway resulted in accumulation of undifferentiated cells throughout the animal in an abnormal transcriptional state. Analysis of >1,000 planarian gene expression datasets revealed that the inhibition of the chromatin modifying complex NuRD had almost indistinguishable consequences, unraveling an unappreciated link between m6A and chromatin modifications. Our findings reveal that m6A is critical for planarian stem cell homeostasis and gene regulation in tissue maintenance and regeneration.
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Affiliation(s)
- Yael Dagan
- The George S. Wise Faculty of Life Sciences, School of Neurobiology, Biochemistry, and Biophysics, Tel Aviv University, Tel Aviv, Israel
| | - Yarden Yesharim
- The George S. Wise Faculty of Life Sciences, School of Neurobiology, Biochemistry, and Biophysics, Tel Aviv University, Tel Aviv, Israel
| | - Ashley R Bonneau
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Tamar Frankovits
- The George S. Wise Faculty of Life Sciences, School of Neurobiology, Biochemistry, and Biophysics, Tel Aviv University, Tel Aviv, Israel
| | - Schraga Schwartz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Peter W Reddien
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Omri Wurtzel
- The George S. Wise Faculty of Life Sciences, School of Neurobiology, Biochemistry, and Biophysics, Tel Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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15
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Ge XY, Han X, Zhao YL, Cui GS, Yang YG. An insight into planarian regeneration. Cell Prolif 2022; 55:e13276. [PMID: 35811385 PMCID: PMC9436907 DOI: 10.1111/cpr.13276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/22/2022] [Accepted: 05/17/2022] [Indexed: 11/29/2022] Open
Abstract
Background Planarian has attracted increasing attentions in the regeneration field for its usefulness as an important biological model organism attributing to its strong regeneration ability. Both the complexity of multiple regulatory networks and their coordinate functions contribute to the maintenance of normal cellular homeostasis and the process of regeneration in planarian. The polarity, size, location and number of regeneration tissues are regulated by diverse mechanisms. In this review we summarize the recent advances about the importance genetic and molecular mechanisms for regeneration control on various tissues in planarian. Methods A comprehensive literature search of original articles published in recent years was performed in regards to the molecular mechanism of each cell types during the planarian regeneration, including neoblast, nerve system, eye spot, excretory system and epidermal. Results Available molecular mechanisms gave us an overview of regeneration process in every tissue. The sense of injuries and initiation of regeneration is regulated by diverse genes like follistatin and ERK signaling. The Neoblasts differentiate into tissue progenitors under the regulation of genes such as egfr‐3. The regeneration polarity is controlled by Wnt pathway, BMP pathway and bioelectric signals. The neoblast within the blastema differentiate into desired cell types and regenerate the missing tissues. Those tissue specific genes regulate the tissue progenitor cells to differentiate into desired cell types to complete the regeneration process. Conclusion All tissue types in planarian participate in the regeneration process regulated by distinct molecular factors and cellular signaling pathways. The neoblasts play vital roles in tissue regeneration and morphology maintenance. These studies provide new insights into the molecular mechanisms for regulating planarian regeneration.
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Affiliation(s)
- Xin-Yang Ge
- CAS Key Laboratory of Genomic and Precision Medicine, Collaborative Innovation Center of Genetics and Development, College of Future Technology, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China.,Sino-Danish College, University of Chinese Academy of Sciences, Beijing, China.,China National Center for Bioinformation, Beijing, China
| | - Xiao Han
- Center for Reproductive Medicine, Henan Key Laboratory of Reproduction and Genetics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yong-Liang Zhao
- CAS Key Laboratory of Genomic and Precision Medicine, Collaborative Innovation Center of Genetics and Development, College of Future Technology, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China.,Sino-Danish College, University of Chinese Academy of Sciences, Beijing, China.,China National Center for Bioinformation, Beijing, China
| | - Guan-Shen Cui
- CAS Key Laboratory of Genomic and Precision Medicine, Collaborative Innovation Center of Genetics and Development, College of Future Technology, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China.,China National Center for Bioinformation, Beijing, China
| | - Yun-Gui Yang
- CAS Key Laboratory of Genomic and Precision Medicine, Collaborative Innovation Center of Genetics and Development, College of Future Technology, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China.,Sino-Danish College, University of Chinese Academy of Sciences, Beijing, China.,China National Center for Bioinformation, Beijing, China
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16
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Wong LL, Bruxvoort CG, Cejda NI, Delaney MR, Otero JR, Forsthoefel DJ. Intestine-enriched apolipoprotein b orthologs are required for stem cell progeny differentiation and regeneration in planarians. Nat Commun 2022; 13:3803. [PMID: 35778403 PMCID: PMC9249923 DOI: 10.1038/s41467-022-31385-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 06/16/2022] [Indexed: 02/08/2023] Open
Abstract
Lipid metabolism plays an instructive role in regulating stem cell state and differentiation. However, the roles of lipid mobilization and utilization in stem cell-driven regeneration are unclear. Planarian flatworms readily restore missing tissue due to injury-induced activation of pluripotent somatic stem cells called neoblasts. Here, we identify two intestine-enriched orthologs of apolipoprotein b, apob-1 and apob-2, which mediate transport of neutral lipid stores from the intestine to target tissues including neoblasts, and are required for tissue homeostasis and regeneration. Inhibition of apob function by RNAi causes head regression and lysis in uninjured animals, and delays body axis re-establishment and regeneration of multiple organs in amputated fragments. Furthermore, apob RNAi causes expansion of the population of differentiating neoblast progeny and dysregulates expression of genes enriched in differentiating and mature cells in eight major cell type lineages. We conclude that intestine-derived lipids serve as a source of metabolites required for neoblast progeny differentiation.
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Affiliation(s)
- Lily L Wong
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Christina G Bruxvoort
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Veteran Affairs Medical Center - Research Services, Oklahoma City, OK, USA
| | - Nicholas I Cejda
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Center for Biomedical Data Science, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Matthew R Delaney
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Jannette Rodriguez Otero
- Howard Hughes Medical Institute, Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Education, Universidad Interamericana de Puerto Rico, San Juan, Puerto Rico, USA
| | - David J Forsthoefel
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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17
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Tian Q, Sun Y, Gao T, Li J, Fang H, Zhang S. Djnedd4L Is Required for Head Regeneration by Regulating Stem Cell Maintenance in Planarians. Int J Mol Sci 2021; 22:ijms222111707. [PMID: 34769140 PMCID: PMC8583885 DOI: 10.3390/ijms222111707] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/22/2021] [Accepted: 10/24/2021] [Indexed: 12/02/2022] Open
Abstract
SUMOylation and ubiquitylation are homologous processes catalyzed by homologous enzymes, and they are involved in nearly all aspects of eukaryotic biology. Planarians, which have the remarkable ability to regenerate their central nervous system (CNS), provide an excellent opportunity to investigate the molecular processes of CNS regeneration in vivo. In this study, we analyzed gene expression profiles during head regeneration with an RNA-seq-based screening approach and found that Djnedd4L and Djubc9 were required for head regeneration in planarians. RNA interference targeting of Djubc9 caused the phospho-H3 mitotic cells to decrease in quantity, or even become absent as a part of the Djubc9 RNAi phenotype, which also showed the collapse of the stem cell lineage along with the reduced expression of epidermal differentiation markers. Furthermore, we found that Djnedd4L RNAi induced increased cell division and promoted the premature differentiation during regeneration. Taken together, our findings show that Djubc9 and Djnedd4L are required for stem cell maintenance in the planarian Dugesia japonica, which helps to elucidate the role of SUMOylation and ubiquitylation in regulating the regeneration process.
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Affiliation(s)
- Qingnan Tian
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.T.); (Y.S.); (T.G.); (J.L.)
| | - Yujia Sun
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.T.); (Y.S.); (T.G.); (J.L.)
| | - Tingting Gao
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.T.); (Y.S.); (T.G.); (J.L.)
| | - Jiaxin Li
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.T.); (Y.S.); (T.G.); (J.L.)
| | - Huimin Fang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.T.); (Y.S.); (T.G.); (J.L.)
- Correspondence: (H.F.); (S.Z.)
| | - Shoutao Zhang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.T.); (Y.S.); (T.G.); (J.L.)
- Henan Key Laboratory of Bioactive Macromolecules, Zhengzhou 450001, China
- Correspondence: (H.F.); (S.Z.)
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18
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Molina MD, Cebrià F. Decoding Stem Cells: An Overview on Planarian Stem Cell Heterogeneity and Lineage Progression. Biomolecules 2021; 11:1532. [PMID: 34680165 PMCID: PMC8533874 DOI: 10.3390/biom11101532] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 01/26/2023] Open
Abstract
Planarians are flatworms capable of whole-body regeneration, able to regrow any missing body part after injury or amputation. The extraordinary regenerative capacity of planarians is based upon the presence in the adult of a large population of somatic pluripotent stem cells. These cells, called neoblasts, offer a unique system to study the process of stem cell specification and differentiation in vivo. In recent years, FACS-based isolation of neoblasts, RNAi functional analyses as well as high-throughput approaches such as single-cell sequencing have allowed a rapid progress in our understanding of many different aspects of neoblast biology. Here, we summarize our current knowledge on the molecular signatures that define planarian neoblasts heterogeneity, which includes a percentage of truly pluripotent stem cells, and guide the commitment of pluripotent neoblasts into lineage-specific progenitor cells, as well as their differentiation into specific planarian cell types.
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Affiliation(s)
- M. Dolores Molina
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Institute of Biomedicine of the University of Barcelona (IBUB), 08028 Barcelona, Spain
| | - Francesc Cebrià
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Institute of Biomedicine of the University of Barcelona (IBUB), 08028 Barcelona, Spain
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19
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Li D, Taylor DH, van Wolfswinkel JC. PIWI-mediated control of tissue-specific transposons is essential for somatic cell differentiation. Cell Rep 2021; 37:109776. [PMID: 34610311 PMCID: PMC8532177 DOI: 10.1016/j.celrep.2021.109776] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/27/2021] [Accepted: 09/07/2021] [Indexed: 12/24/2022] Open
Abstract
PIWI proteins are known as mediators of transposon silencing in animal germlines but are also found in adult pluripotent stem cells of highly regenerative animals, where they are essential for regeneration. Study of the nuclear PIWI protein SMEDWI-2 in the planarian somatic stem cell system reveals an intricate interplay between transposons and cell differentiation in which a subset of transposons is inevitably activated during cell differentiation, and the PIWI protein is required to regain control. Absence of SMEDWI-2 leads to tissue-specific transposon derepression related to cell-type-specific chromatin remodeling events and in addition causes reduced accessibility of lineage-specific genes and defective cell differentiation, resulting in fatal tissue dysfunction. Finally, we show that additional PIWI proteins provide a stem-cell-specific second layer of protection in planarian neoblasts. These findings reveal a far-reaching role of PIWI proteins and PIWI-interacting RNAs (piRNAs) in stem cell biology and cell differentiation.
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Affiliation(s)
- Danyan Li
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - David H Taylor
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Josien C van Wolfswinkel
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA.
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20
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Benham-Pyle BW, Brewster CE, Kent AM, Mann FG, Chen S, Scott AR, Box AC, Sánchez Alvarado A. Identification of rare, transient post-mitotic cell states that are induced by injury and required for whole-body regeneration in Schmidtea mediterranea. Nat Cell Biol 2021; 23:939-952. [PMID: 34475533 PMCID: PMC8855990 DOI: 10.1038/s41556-021-00734-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 07/14/2021] [Indexed: 01/02/2023]
Abstract
Regeneration requires the coordination of stem cells, their progeny and distant differentiated tissues. Here, we present a comprehensive atlas of whole-body regeneration in Schmidtea mediterranea and identify wound-induced cell states. An analysis of 299,998 single-cell transcriptomes captured from regeneration-competent and regeneration-incompetent fragments identified transient regeneration-activated cell states (TRACS) in the muscle, epidermis and intestine. TRACS were independent of stem cell division with distinct spatiotemporal distributions, and RNAi depletion of TRACS-enriched genes produced regeneration defects. Muscle expression of notum, follistatin, evi/wls, glypican-1 and junctophilin-1 was required for tissue polarity. Epidermal expression of agat-1/2/3, cyp3142a1, zfhx3 and atp1a1 was important for stem cell proliferation. Finally, expression of spectrinβ and atp12a in intestinal basal cells, and lrrk2, cathepsinB, myosin1e, polybromo-1 and talin-1 in intestinal enterocytes regulated stem cell proliferation and tissue remodelling, respectively. Our results identify cell types and molecules that are important for regeneration, indicating that regenerative ability can emerge from coordinated transcriptional plasticity across all three germ layers.
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Affiliation(s)
- Blair W Benham-Pyle
- Stowers Institute for Medical Research, Kansas City, MO, USA.
- Howard Hughes Institute for Medical Research, Kansas City, MO, USA.
| | | | - Aubrey M Kent
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Frederick G Mann
- Stowers Institute for Medical Research, Kansas City, MO, USA
- Howard Hughes Institute for Medical Research, Kansas City, MO, USA
| | - Shiyuan Chen
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Allison R Scott
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Andrew C Box
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Alejandro Sánchez Alvarado
- Stowers Institute for Medical Research, Kansas City, MO, USA.
- Howard Hughes Institute for Medical Research, Kansas City, MO, USA.
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21
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Albarqi MMY, Ryder SP. The endogenous mex-3 3´UTR is required for germline repression and contributes to optimal fecundity in C. elegans. PLoS Genet 2021; 17:e1009775. [PMID: 34424904 PMCID: PMC8412283 DOI: 10.1371/journal.pgen.1009775] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 09/02/2021] [Accepted: 08/11/2021] [Indexed: 11/18/2022] Open
Abstract
RNA regulation is essential to successful reproduction. Messenger RNAs delivered from parent to progeny govern early embryonic development. RNA-binding proteins (RBPs) are the key effectors of this process, regulating the translation and stability of parental transcripts to control cell fate specification events prior to zygotic gene activation. The KH-domain RBP MEX-3 is conserved from nematode to human. It was first discovered in Caenorhabditis elegans, where it is essential for anterior cell fate and embryo viability. Here, we show that loss of the endogenous mex-3 3´UTR disrupts its germline expression pattern. An allelic series of 3´UTR deletion variants identify repressing regions of the UTR and demonstrate that repression is not precisely coupled to reproductive success. We also show that several RBPs regulate mex-3 mRNA through its 3´UTR to define its unique germline spatiotemporal expression pattern. Additionally, we find that both poly(A) tail length control and the translation initiation factor IFE-3 contribute to its expression pattern. Together, our results establish the importance of the mex-3 3´UTR to reproductive health and its expression in the germline. Our results suggest that additional mechanisms control MEX-3 function when 3´UTR regulation is compromised. In sexually reproducing organisms, germ cells undergo meiosis and differentiate to form oocytes or sperm. Coordination of this process requires a gene regulatory program that acts while the genome is undergoing chromatin condensation. As such, RNA regulatory pathways are an important contributor. The germline of the nematode Caenorhabditis elegans is a suitable model system to study germ cell differentiation. Several RNA-binding proteins (RBPs) coordinate each transition in the germline such as the transition from mitosis to meiosis. MEX-3 is a conserved RNA-binding protein found in most animals including humans. In C. elegans, MEX-3 displays a highly restricted pattern of expression. Here, we define the importance of the 3´UTR in regulating MEX-3 expression pattern in vivo and characterize the RNA-binding proteins involved in this regulation. Our results show that deleting various mex-3 3´UTR regions alter the pattern of expression in the germline in various ways. These mutations also reduced—but did not eliminate—reproductive capacity. Finally, we demonstrate that multiple post-transcriptional mechanisms control MEX-3 levels in different domains of the germline. Our data suggest that coordination of MEX-3 activity requires multiple layers of regulation to ensure reproductive robustness.
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Affiliation(s)
- Mennatallah M. Y. Albarqi
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Sean P. Ryder
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
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22
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Bohr TE, Shiroor DA, Adler CE. Planarian stem cells sense the identity of the missing pharynx to launch its targeted regeneration. eLife 2021; 10:e68830. [PMID: 34156924 PMCID: PMC8219383 DOI: 10.7554/elife.68830] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/22/2021] [Indexed: 12/25/2022] Open
Abstract
In order to regenerate tissues successfully, stem cells must detect injuries and restore missing cell types through largely unknown mechanisms. Planarian flatworms have an extensive stem cell population responsible for regenerating any organ after amputation. Here, we compare planarian stem cell responses to different injuries by either amputation of a single organ, the pharynx, or removal of tissues from other organs by decapitation. We find that planarian stem cells adopt distinct behaviors depending on what tissue is missing to target progenitor and tissue production towards missing tissues. Loss of non-pharyngeal tissues only increases non-pharyngeal progenitors, while pharynx removal selectively triggers division and expansion of pharynx progenitors. By pharmacologically inhibiting either mitosis or activation of the MAP kinase ERK, we identify a narrow window of time during which stem cell division and ERK signaling produces pharynx progenitors necessary for regeneration. These results indicate that planarian stem cells can tailor their output to match the regenerative needs of the animal.
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Affiliation(s)
- Tisha E Bohr
- Department of Molecular Medicine, Cornell University College of Veterinary MedicineIthacaUnited States
| | - Divya A Shiroor
- Department of Molecular Medicine, Cornell University College of Veterinary MedicineIthacaUnited States
| | - Carolyn E Adler
- Department of Molecular Medicine, Cornell University College of Veterinary MedicineIthacaUnited States
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23
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Raz AA, Wurtzel O, Reddien PW. Planarian stem cells specify fate yet retain potency during the cell cycle. Cell Stem Cell 2021; 28:1307-1322.e5. [PMID: 33882291 DOI: 10.1016/j.stem.2021.03.021] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 01/08/2021] [Accepted: 03/25/2021] [Indexed: 02/06/2023]
Abstract
Planarian whole-body regeneration is enabled by stem cells called neoblasts. At least some neoblasts are individually pluripotent. Neoblasts are also heterogeneous, with subpopulations of specialized neoblasts having different specified fates. Fate specification in neoblasts is regulated by fate-specific transcription factor (FSTF) expression. Here, we find that FSTF expression is common in neoblast S/G2/M cell-cycle phases but less common in G1. We find that specialized neoblasts can divide to produce progeny with asymmetric cell fates, suggesting that they could retain pluripotency. Furthermore, no known neoblast class was present in all neoblast colonies, suggesting that pluripotency is not the exclusive property of any known class. We tested this possibility with single-cell transplantations, which indicate that at least some specialized neoblasts are likely clonogenic. On the basis of these findings, we propose a model for neoblast pluripotency in which neoblasts can undergo specialization during the cell cycle without loss of potency.
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Affiliation(s)
- Amelie A Raz
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Omri Wurtzel
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Peter W Reddien
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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24
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Collagen IV differentially regulates planarian stem cell potency and lineage progression. Proc Natl Acad Sci U S A 2021; 118:2021251118. [PMID: 33859045 PMCID: PMC8072372 DOI: 10.1073/pnas.2021251118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Comprehensive assessment of matrisome genes identified collagen IV as one of the many extracellular matrix (ECM) proteins regulating the stem cell pool in planarian tissue homeostasis and regeneration. While collagen IV has been shown to be involved in stem cell biology, our finding links it to pluripotent stem cells in vivo, including self-renewal and differentiation into tissue-specific progenitors. We show a link between the ECM niches in the parenchyma/gut region and EGF/neuregulin-secreting neurons, thus providing mechanistic insight into interactions between cell niches. The conservation of basement membranes between planarian and mammalian gut niches suggests a similar interplay may exist in the mammalian systems, worthy of further investigation. The extracellular matrix (ECM) provides a precise physical and molecular environment for cell maintenance, self-renewal, and differentiation in the stem cell niche. However, the nature and organization of the ECM niche is not well understood. The adult freshwater planarian Schmidtea mediterranea maintains a large population of multipotent stem cells (neoblasts), presenting an ideal model to study the role of the ECM niche in stem cell regulation. Here we tested the function of 165 planarian homologs of ECM and ECM-related genes in neoblast regulation. We identified the collagen gene family as one with differential effects in promoting or suppressing proliferation of neoblasts. col4-1, encoding a type IV collagen α-chain, had the strongest effect. RNA interference (RNAi) of col4-1 impaired tissue maintenance and regeneration, causing tissue regression. Finally, we provide evidence for an interaction between type IV collagen, the discoidin domain receptor, and neuregulin-7 (NRG-7), which constitutes a mechanism to regulate the balance of symmetric and asymmetric division of neoblasts via the NRG-7/EGFR pathway.
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25
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Fraguas S, Cárcel S, Vivancos C, Molina MD, Ginés J, Mazariegos J, Sekaran T, Bartscherer K, Romero R, Cebrià F. CREB-binding protein (CBP) gene family regulates planarian survival and stem cell differentiation. Dev Biol 2021; 476:53-67. [PMID: 33774010 DOI: 10.1016/j.ydbio.2021.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 12/21/2022]
Abstract
In developmental biology, the regulation of stem cell plasticity and differentiation remains an open question. CBP(CREB-binding protein)/p300 is a conserved gene family that functions as a transcriptional co-activator and plays important roles in a wide range of cellular processes, including cell death, the DNA damage response, and tumorigenesis. The acetyl transferase activity of CBPs is particularly important, as histone and non-histone acetylation results in changes in chromatin architecture and protein activity that affect gene expression. Many studies have described the conserved functions of CBP/p300 in stem cell proliferation and differentiation. The planarian Schmidtea mediterranea is an excellent model for the in vivo study of the molecular mechanisms underlying stem cell differentiation during regeneration. However, how this process is regulated genetically and epigenetically is not well-understood yet. We identified 5 distinct Smed-cbp genes in S. mediterranea that show different expression patterns. Functional analyses revealed that Smed-cbp-2 appears to be essential for stem cell maintenance. On the other hand, the silencing of Smed-cbp-3 resulted in the growth of blastemas that were apparently normal, but remained largely unpigmented and undifferentiated. Smed-cbp-3 silencing also affected the differentiation of several cell lineages including neural, epidermal, digestive, and excretory cell types. Finally, we analysed the predicted interactomes of CBP-2 and CBP-3 as an initial step to better understand their functions in planarian stem cell biology. Our results indicate that planarian cbp genes play key roles in stem cell maintenance and differentiation.
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Affiliation(s)
- Susanna Fraguas
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Spain
| | - Sheila Cárcel
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Spain
| | - Coral Vivancos
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Spain
| | - Ma Dolores Molina
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Spain
| | - Jordi Ginés
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Spain
| | - Judith Mazariegos
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Spain
| | | | | | - Rafael Romero
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Spain
| | - Francesc Cebrià
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Spain.
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Canonical and early lineage-specific stem cell types identified in planarian SirNeoblasts. CELL REGENERATION 2021; 10:15. [PMID: 33740162 PMCID: PMC7979843 DOI: 10.1186/s13619-021-00076-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/12/2021] [Indexed: 12/28/2022]
Abstract
BACKGROUND The pluripotent stem cells in planarians, a model for tissue and cellular regeneration, remain further identification. We recently developed a method to enrich piwi-1+ cells in Schmidtea mediterranea, by staining cells with SiR-DNA and Cell Tracker Green, named SirNeoblasts that permits their propagation and subsequent functional study in vivo. Since traditional enrichment for planarian neoblasts by Hoechst 33342 staining generates X1 cells, blocking the cell cycle and inducing cytotoxicity, this method by SiR-DNA and Cell Tracker Green represents a complementary technological advance for functional investigation of cell fate and regeneration. However, the similarities in heterogeneity of cell subtypes between SirNeoblasts and X1 remain unknown. RESULTS In this work, we performed single cell RNA sequencing of SirNeoblasts for comparison with differential expression patterns in a publicly available X1 single cell RNA sequencing data. We found first that all of the lineage-specific progenitor cells in X1 were present in comparable proportions in SirNeoblasts. In addition, SirNeoblasts contain an early muscle progenitor that is unreported in X1. Analysis of new markers for putative pluripotent stem cells identified here, with subsequent sub-clustering analysis, revealed earlier lineages of epidermal, muscular, intestinal, and pharyngeal progenitors than have been observed in X1. Using the gcm as a marker, we also identified a cell subpopulation resided in previously identified tgs-1+ neoblasts. Knockdown of gcm impaired the neoblast repopulation, suggesting a function of gcm in neoblasts. CONCLUSIONS In summary, the use of SirNeoblasts will enable broad experimental advances in regeneration and cell fate specification, given the possibility for propagation and transplantation of recombinant and mutagenized pluripotent stem cells that are not previously afforded to this rapid and versatile model system.
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Molinaro AM, Lindsay‐Mosher N, Pearson BJ. Identification of TOR-responsive slow-cycling neoblasts in planarians. EMBO Rep 2021; 22:e50292. [PMID: 33511776 PMCID: PMC7926258 DOI: 10.15252/embr.202050292] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 11/19/2020] [Accepted: 12/14/2020] [Indexed: 12/11/2022] Open
Abstract
Epimorphic regeneration commonly relies on the activation of reserved stem cells to drive new cell production. The planarian Schmidtea mediterranea is among the best regenerators in nature, thanks to its large population of adult stem cells, called neoblasts. While neoblasts have long been known to drive regeneration, whether a subset of neoblasts is reserved for this purpose is unknown. Here, we revisit the idea of reserved neoblasts by approaching neoblast heterogeneity from a regulatory perspective. By implementing a new fluorescence-activated cell sorting strategy in planarians, we identify a population of neoblasts defined by low transcriptional activity. These RNAlow neoblasts are relatively slow-cycling at homeostasis and undergo a morphological regeneration response characterized by cell growth at 48 h post-amputation. At this time, RNAlow neoblasts proliferate in a TOR-dependent manner. Additionally, knockdown of the tumour suppressor Lrig-1, which is enriched in RNAlow neoblasts, results in RNAlow neoblast growth and hyperproliferation at homeostasis, and ultimately delays regeneration. We propose that slow-cycling RNAlow neoblasts represent a regeneration-reserved neoblast population.
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Affiliation(s)
- Alyssa M Molinaro
- Program in Developmental and Stem Cell BiologyHospital for Sick ChildrenTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
- Present address:
Department of Systems BiologyHarvard Medical SchoolBostonMAUSA
| | - Nicole Lindsay‐Mosher
- Program in Developmental and Stem Cell BiologyHospital for Sick ChildrenTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
| | - Bret J Pearson
- Program in Developmental and Stem Cell BiologyHospital for Sick ChildrenTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
- Ontario Institute for Cancer ResearchTorontoONCanada
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Pryszlak M, Wiggans M, Chen X, Jaramillo JE, Burns SE, Richards LM, Pugh TJ, Kaplan DR, Huang X, Dirks PB, Pearson BJ. The DEAD-box helicase DDX56 is a conserved stemness regulator in normal and cancer stem cells. Cell Rep 2021; 34:108903. [PMID: 33789112 DOI: 10.1016/j.celrep.2021.108903] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 10/28/2020] [Accepted: 03/04/2021] [Indexed: 12/12/2022] Open
Abstract
Across the animal kingdom, adult tissue homeostasis is regulated by adult stem cell activity, which is commonly dysregulated in human cancers. However, identifying key regulators of stem cells in the milieu of thousands of genes dysregulated in a given cancer is challenging. Here, using a comparative genomics approach between planarian adult stem cells and patient-derived glioblastoma stem cells (GSCs), we identify and demonstrate the role of DEAD-box helicase DDX56 in regulating aspects of stemness in four stem cell systems: planarians, mouse neural stem cells, human GSCs, and a fly model of glioblastoma. In a human GSC line, DDX56 localizes to the nucleolus, and using planarians, when DDX56 is lost, stem cells dysregulate expression of ribosomal RNAs and lose nucleolar integrity prior to stem cell death. Together, a comparative genomic approach can be used to uncover conserved stemness regulators that are functional in both normal and cancer stem cells.
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Affiliation(s)
- Michael Pryszlak
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G 0A4, Canada; University of Toronto, Department of Molecular Genetics, Toronto, ON M5S 1A8, Canada
| | - Mallory Wiggans
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G 0A4, Canada; University of Toronto, Department of Molecular Genetics, Toronto, ON M5S 1A8, Canada
| | - Xin Chen
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G 0A4, Canada
| | - Julia E Jaramillo
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G 0A4, Canada; University of Toronto, Department of Molecular Genetics, Toronto, ON M5S 1A8, Canada
| | - Sarah E Burns
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G 0A4, Canada
| | - Laura M Richards
- Department of Medical Biophysics, University of Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2C1, Canada
| | - Trevor J Pugh
- Ontario Institute for Cancer Research, Toronto, ON M5G 0A3, Canada; Department of Medical Biophysics, University of Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2C1, Canada
| | - David R Kaplan
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G 0A4, Canada; University of Toronto, Department of Molecular Genetics, Toronto, ON M5S 1A8, Canada
| | - Xi Huang
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G 0A4, Canada; University of Toronto, Department of Molecular Genetics, Toronto, ON M5S 1A8, Canada; Ontario Institute for Cancer Research, Toronto, ON M5G 0A3, Canada; The Hospital for Sick Children, Arthur and Sonia Labatt Brain Tumor Research Centre, Toronto, ON M5G 0A4, Canada
| | - Peter B Dirks
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G 0A4, Canada; University of Toronto, Department of Molecular Genetics, Toronto, ON M5S 1A8, Canada; Ontario Institute for Cancer Research, Toronto, ON M5G 0A3, Canada; The Hospital for Sick Children, Arthur and Sonia Labatt Brain Tumor Research Centre, Toronto, ON M5G 0A4, Canada
| | - Bret J Pearson
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G 0A4, Canada; University of Toronto, Department of Molecular Genetics, Toronto, ON M5S 1A8, Canada; Ontario Institute for Cancer Research, Toronto, ON M5G 0A3, Canada.
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Cao Z, Rosenkranz D, Wu S, Liu H, Pang Q, Zhang X, Liu B, Zhao B. Different classes of small RNAs are essential for head regeneration in the planarian Dugesia japonica. BMC Genomics 2020; 21:876. [PMID: 33287698 PMCID: PMC7722302 DOI: 10.1186/s12864-020-07234-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 11/17/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Planarians reliably regenerate all body parts after injury, including a fully functional head and central nervous system. But until now, the expression dynamics and functional role of miRNAs and other small RNAs during the process of head regeneration are not well understood. Furthermore, little is known about the evolutionary conservation of the relevant small RNAs pathways, rendering it difficult to assess whether insights from planarians will apply to other taxa. RESULTS In this study, we applied high throughput sequencing to identify miRNAs, tRNA fragments and piRNAs that are dynamically expressed during head regeneration in Dugesia japonica. We further show that knockdown of selected small RNAs, including three novel Dugesia-specific miRNAs, during head regeneration induces severe defects including abnormally small-sized eyes, cyclopia and complete absence of eyes. CONCLUSIONS Our findings suggest that a complex pool of small RNAs takes part in the process of head regeneration in Dugesia japonica and provide novel insights into global small RNA expression profiles and expression changes in response to head amputation. Our study reveals the evolutionary conserved role of miR-124 and brings further promising candidate small RNAs into play that might unveil new avenues for inducing restorative programs in non-regenerative organisms via small RNA mimics based therapies.
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Affiliation(s)
- Zhonghong Cao
- grid.412509.b0000 0004 1808 3414School of Life Sciences, Shandong University of Technology, 266 Xincun Western Road, Zibo, 255049 People’s Republic of China
| | - David Rosenkranz
- grid.5802.f0000 0001 1941 7111Institute of Organismic and Molecular Evolution (iOME), Anthropology, Anselm-Franz-von-Bentzel-Weg 7, Johannes Gutenberg University, 55099 Mainz, Germany
| | - Suge Wu
- grid.412509.b0000 0004 1808 3414School of Life Sciences, Shandong University of Technology, 266 Xincun Western Road, Zibo, 255049 People’s Republic of China
| | - Hongjin Liu
- grid.412509.b0000 0004 1808 3414School of Life Sciences, Shandong University of Technology, 266 Xincun Western Road, Zibo, 255049 People’s Republic of China
| | - Qiuxiang Pang
- grid.412509.b0000 0004 1808 3414School of Life Sciences, Shandong University of Technology, 266 Xincun Western Road, Zibo, 255049 People’s Republic of China
| | - Xiufang Zhang
- grid.412509.b0000 0004 1808 3414School of Life Sciences, Shandong University of Technology, 266 Xincun Western Road, Zibo, 255049 People’s Republic of China
| | - Baohua Liu
- grid.412509.b0000 0004 1808 3414School of Life Sciences, Shandong University of Technology, 266 Xincun Western Road, Zibo, 255049 People’s Republic of China
| | - Bosheng Zhao
- grid.412509.b0000 0004 1808 3414School of Life Sciences, Shandong University of Technology, 266 Xincun Western Road, Zibo, 255049 People’s Republic of China
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Ziman B, Barghouth PG, Maciel EI, Oviedo NJ. TRAF-like Proteins Regulate Cellular Survival in the Planarian Schmidtea mediterranea. iScience 2020; 23:101665. [PMID: 33134895 PMCID: PMC7586133 DOI: 10.1016/j.isci.2020.101665] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 07/31/2020] [Accepted: 10/07/2020] [Indexed: 12/12/2022] Open
Abstract
Tissue homeostasis relies on the timely renewal of cells that have been damaged or have surpassed their biological age. Nonetheless, the underlying molecular mechanism coordinating tissue renewal is unknown. The planarian Schmidtea mediterranea harbors a large population of stem cells that continuously divide to support the restoration of tissues throughout the body. Here, we identify that TNF Receptor Associated Factors (TRAFs) play critical roles in cellular survival during tissue repair in S. mediterranea. Disruption with RNA-interference of TRAF signaling results in rapid morphological defects and lethality within 2 weeks. The TRAF phenotype is accompanied by an increased number of mitoses and cell death. Our results also reveal TRAF signaling is required for proper regeneration of the nervous system. Taken together, we find functional conservation of TRAF-like proteins in S. mediterranea as they act as crucial regulators of cellular survival during tissue homeostasis and regeneration.
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Affiliation(s)
- Benjamin Ziman
- Department of Molecular and Cell Biology, University of California, Merced, CA 95343, USA
- Quantitative and Systems Biology Graduate Program, University of California, Merced, CA 95343, USA
| | - Paul G. Barghouth
- Department of Molecular and Cell Biology, University of California, Merced, CA 95343, USA
- Quantitative and Systems Biology Graduate Program, University of California, Merced, CA 95343, USA
| | - Eli Isael Maciel
- Department of Molecular and Cell Biology, University of California, Merced, CA 95343, USA
- Quantitative and Systems Biology Graduate Program, University of California, Merced, CA 95343, USA
| | - Néstor J. Oviedo
- Department of Molecular and Cell Biology, University of California, Merced, CA 95343, USA
- Quantitative and Systems Biology Graduate Program, University of California, Merced, CA 95343, USA
- Health Sciences Research Institute, University of California, Merced, CA 95343, USA
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31
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Burrows JTA, Depierreux D, Nibert ML, Pearson BJ. A Novel Taxon of Monosegmented Double-Stranded RNA Viruses Endemic to Triclad Flatworms. J Virol 2020; 94:e00623-20. [PMID: 32907972 PMCID: PMC7592200 DOI: 10.1128/jvi.00623-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 09/01/2020] [Indexed: 12/12/2022] Open
Abstract
Freshwater planarians, flatworms from order Tricladida, are experimental models of stem cell biology and tissue regeneration. An aspect of their biology that remains less well studied is their relationship with viruses that may infect them. In this study, we identified a taxon of monosegmented double-stranded RNA (dsRNA) viruses in five planarian species, including the well-characterized model Schmidtea mediterranea Sequences for the S. mediterranea virus (abbreviated SmedTV for S. mediterranea tricladivirus) were found in public transcriptome data from multiple institutions, indicating that SmedTV is prevalent in S. mediterranea lab colonies, though without causing evident disease. The presence of SmedTV in discrete cells was shown through in situ hybridization methods for detecting the viral RNA. SmedTV-staining cells were found to be concentrated in neural structures (eyes and brain) but were also scattered in other worm tissues as well. In contrast, few SmedTV-staining cells were seen in stem cell compartments (also consistent with RNA sequencing data) or early blastema tissue. RNA interference (RNAi) targeted to the SmedTV sequence led to apparent cure of infection, though effects on worm health or behavior were not observed. Efforts to transmit SmedTV horizontally through microinjection were unsuccessful. Based on these findings, we conclude that SmedTV infects S. mediterranea in a persistent manner and undergoes vertical transmission to progeny worms during serial passage in lab colonies. The utility of S. mediterranea as a regeneration model, coupled with the apparent capacity of SmedTV to evade normal host immune/RNAi defenses under standard conditions, argues that further studies are warranted to explore this newly recognized virus-host system.IMPORTANCE Planarians are freshwater flatworms, related more distantly to tapeworms and flukes, and have been developed as models to study the molecular mechanisms of stem cell biology and tissue regeneration. These worms live in aquatic environments, where they are likely to encounter a variety of viruses, bacteria, and eukaryotic organisms with pathogenic potential. How the planarian immune system has evolved to cope with these potential pathogens is not well understood, and only two types of planarian viruses have been described to date. Here, we report discovery and inaugural studies of a novel taxon of dsRNA viruses in five different planarian species. The virus in the best-characterized model species, Schmidtea mediterranea, appears to persist long term in that host while avoiding endogenous antiviral or RNAi mechanisms. The S. mediterranea virus-host system thus seems to offer opportunity for gaining new insights into host defenses and their evolution in an important lab model.
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Affiliation(s)
- Jeffrey T A Burrows
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, Ontario, Canada
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
| | - Delphine Depierreux
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Max L Nibert
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Bret J Pearson
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, Ontario, Canada
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
- University of Toronto, Department of Molecular Genetics, Toronto, Ontario, Canada
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Ziman B, Karabinis P, Barghouth P, Oviedo NJ. Sirtuin-1 regulates organismal growth by altering feeding behavior and intestinal morphology in planarians. J Cell Sci 2020; 133:jcs239467. [PMID: 32265271 PMCID: PMC7272345 DOI: 10.1242/jcs.239467] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 03/19/2020] [Indexed: 01/03/2023] Open
Abstract
Nutrient availability upon feeding leads to an increase in body size in the planarian Schmidtea mediterranea However, it remains unclear how food consumption integrates with cell division at the organismal level. Here, we show that the NAD-dependent protein deacetylases sirtuins are evolutionarily conserved in planarians, and specifically demonstrate that the homolog of human sirtuin-1 (SIRT1) (encoded by Smed-Sirt-1), regulates organismal growth by impairing both feeding behavior and intestinal morphology. Disruption of Smed-Sirt-1 with RNAi or pharmacological inhibition of Sirtuin-1 leads to reduced animal growth. Conversely, enhancement of Sirtuin-1 activity with resveratrol accelerates growth. Differences in growth rates were associated with changes in the amount of time taken to locate food and overall food consumption. Furthermore, Smed-Sirt-1(RNAi) animals displayed reduced cell death and increased stem cell proliferation accompanied by impaired expression of intestinal lineage progenitors and reduced branching of the gut. Taken together, our findings indicate that Sirtuin-1 is a crucial metabolic hub capable of controlling animal behavior, tissue renewal and morphogenesis of the adult intestine.
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Affiliation(s)
- Benjamin Ziman
- Department of Molecular and Cell Biology, University of California, Merced, CA 95343, USA
- Quantitative and Systems Biology Graduate Program, University of California, Merced, CA 95343, USA
| | - Peter Karabinis
- Department of Molecular and Cell Biology, University of California, Merced, CA 95343, USA
- Quantitative and Systems Biology Graduate Program, University of California, Merced, CA 95343, USA
| | - Paul Barghouth
- Department of Molecular and Cell Biology, University of California, Merced, CA 95343, USA
- Quantitative and Systems Biology Graduate Program, University of California, Merced, CA 95343, USA
| | - Néstor J Oviedo
- Department of Molecular and Cell Biology, University of California, Merced, CA 95343, USA
- Quantitative and Systems Biology Graduate Program, University of California, Merced, CA 95343, USA
- Health Sciences Research Institute, University of California, Merced, CA 95343, USA
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Planarian EGF repeat-containing genes megf6 and hemicentin are required to restrict the stem cell compartment. PLoS Genet 2020; 16:e1008613. [PMID: 32078629 PMCID: PMC7059952 DOI: 10.1371/journal.pgen.1008613] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 03/06/2020] [Accepted: 01/16/2020] [Indexed: 12/17/2022] Open
Abstract
The extracellular matrix (ECM) is important for maintaining the boundaries between tissues. This role is particularly critical in the stem cell niche, as pre-neoplastic or cancerous stem cells must pass these boundaries in order to invade into the surrounding tissue. Here, we examine the role of the ECM as a regulator of the stem cell compartment in the planarian Schmidtea mediterranea, a highly regenerative, long-lived organism with a large population of adult stem cells. We identify two EGF repeat-containing genes, megf6 and hemicentin, with identical knockdown phenotypes. We find that megf6 and hemicentin are needed to maintain the structure of the basal lamina, and in the absence of either gene, pluripotent stem cells migrate ectopically outside of their compartment and hyper-proliferate, causing lesions in the body wall muscle. These muscle lesions and ectopic stem cells are also associated with ectopic gut branches, which protrude from the normal gut towards the dorsal side of the animal. Interestingly, both megf6 and hemicentin knockdown worms are capable of regenerating tissue free of both muscle lesions and ectopic cells, indicating that these genes are dispensable for regeneration. These results provide insight into the role of planarian ECM in restricting the stem cell compartment, and suggest that signals within the compartment may act to suppress stem cell hyperproliferation. The freshwater planarian maintains a large population of adult stem cells throughout its long lifespan. Although these stem cells are constantly dividing, the rate of division is tightly controlled to such a degree that planarians almost never develop neoplastic growths. In addition, the stem cells are located in a specific spatial compartment within the animal, although no known physical boundary keeps them in place. What mechanisms do planarians use to control the number, rate of division, and location of their stem cells? Here, we find that two EGF repeat-containing genes, megf6 and hemicentin, are required to keep stem cells within their compartment. Although these two genes are expressed in different cell populations, we find that both are required to maintain the epithelial basal lamina. In the absence of either gene, stem cells can escape their compartment and migrate towards the skin of the animal, where they divide at an accelerated rate and cause lesions in the muscle. These results show that the extracellular matrix plays a role in limiting the boundaries of the stem cell compartment.
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Smed-myb-1 Specifies Early Temporal Identity during Planarian Epidermal Differentiation. Cell Rep 2020; 25:38-46.e3. [PMID: 30282036 DOI: 10.1016/j.celrep.2018.09.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/28/2018] [Accepted: 09/06/2018] [Indexed: 12/11/2022] Open
Abstract
The planarian epidermis provides an excellent model to explore adult stem cell (ASC) lineage development due to well-characterized and distinct spatiotemporal phases during lineage progression. Using flow cytometry-isolated cells enriched in epidermal progenitors, we performed transcriptional profiling and RNAi screening to uncover regulators of epidermal differentiation. We identified a MYB-type transcription factor (Smed-myb-1) required for the specification of the first temporal phase of post-mitotic maturation. Knockdown of myb-1 abolished the early progenitor phase of differentiation without ceasing production of subsequent epidermal progenitor states or homeostatic turnover and regeneration of the epidermis. Further examination revealed accelerated maturation of ASC descendants, with premature entry into subsequent progeny phases and, ultimately, the epidermis. These results demonstrate that a spatiotemporal shift in lineage progression occurs in the absence of the early progenitor state after myb-1 RNAi, and identify myb-1 as a critical regulator of the early temporal window in stepwise specification during planarian epidermal differentiation.
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Kimball C, Powers K, Dustin J, Poirier V, Pellettieri J. The exon junction complex is required for stem and progenitor cell maintenance in planarians. Dev Biol 2020; 457:119-127. [PMID: 31557470 PMCID: PMC8544814 DOI: 10.1016/j.ydbio.2019.09.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 07/31/2019] [Accepted: 09/20/2019] [Indexed: 12/12/2022]
Abstract
Named for its assembly near exon-exon junctions during pre-mRNA splicing, the exon junction complex (EJC) regulates multiple aspects of RNA biochemistry, including export of spliced mRNAs from the nucleus and translation. Transcriptome analyses have revealed broad EJC occupancy of spliced metazoan transcripts, yet inhibition of core subunits has been linked to surprisingly specific phenotypes and a growing number of studies support gene-specific regulatory roles. Here we report results from a classroom-based RNAi screen revealing the EJC is necessary for regeneration in the planarian flatworm Schmidtea mediterranea. RNAi animals rapidly lost the stem and progenitor cells that drive formation of new tissue during both regeneration and cell turnover, but exhibited normal amputation-induced changes in gene expression in differentiated tissues. Together with previous reports that partial loss of EJC function causes stem cell defects in Drosophila and mice, our observations implicate the EJC as a conserved, posttranscriptional regulator of gene expression in stem cell lineages. This work also highlights the combined educational and scientific impacts of discovery-based research in the undergraduate biology curriculum.
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Affiliation(s)
- Casey Kimball
- Department of Biology, Keene State College, Keene, NH, USA
| | - Kaleigh Powers
- Department of Biology, Keene State College, Keene, NH, USA
| | - John Dustin
- Department of Biology, Keene State College, Keene, NH, USA
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36
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The Cellular and Molecular Basis for Planarian Regeneration. Cell 2019; 175:327-345. [PMID: 30290140 DOI: 10.1016/j.cell.2018.09.021] [Citation(s) in RCA: 180] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/07/2018] [Accepted: 09/12/2018] [Indexed: 01/03/2023]
Abstract
Regeneration is one of the great mysteries of biology. Planarians are flatworms capable of dramatic feats of regeneration, which have been studied for over 2 centuries. Recent findings identify key cellular and molecular principles underlying these feats. A stem cell population (neoblasts) generates new cells and is comprised of pluripotent stem cells (cNeoblasts) and fate-specified cells (specialized neoblasts). Positional information is constitutively active and harbored primarily in muscle, where it acts to guide stem cell-mediated tissue turnover and regeneration. I describe here a model in which positional information and stem cells combine to enable regeneration.
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Tian Q, Zhao G, Sun Y, Yuan D, Guo Q, Zhang Y, Liu J, Zhang S. Exportin-1 is required for the maintenance of the planarian epidermal lineage. Int J Biol Macromol 2019; 126:1050-1055. [PMID: 30615964 DOI: 10.1016/j.ijbiomac.2019.01.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 01/03/2019] [Accepted: 01/03/2019] [Indexed: 01/27/2023]
Abstract
Nucleocytoplasmic transport is essential for normal cellular function that mediates cargo transport from the cytoplasm to the nucleus. However, the mechanisms of nucleocytoplasmic transport that integrate stem cell development remain largely unknown. Since it has a large population of stem cells, the planarian flatworm is an ideal system for the study of adult stem cell lineage development in vivo. Here, we focus on exportin-1, which is the most conserved nuclear export receptor. Homologs of exportin-1 have no currently known role in stem cell biology. RNA interference targeting exportin-1 caused a failure in anterior and posterior regeneration, and resulted in curly and lysis phenotypes in both intact and regenerating flatworms. During the course of exportin-1 RNAi phenotype, cell division was significantly decreased, and the expression of the epidermal cell markers (vimentin and laminB) were lost from the intact body. Additionally, the expression levels of the neoblast marker piwiA decreased. By contrast, the expression levels of the epidermal progenitor markers NB21.11e and AGAT1 increased. These results suggest that exportin-1 is required for the maintenance of the epidermal lineage in planarians. Inhibition of exportin-1 could promote the premature differentiation of neoblasts to the epidermal lineages, disrupting the proper epidermal maturation.
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Affiliation(s)
- Qingnan Tian
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Guixia Zhao
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Yujia Sun
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Dandan Yuan
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Qi Guo
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Yizhe Zhang
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Jiaqian Liu
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China.
| | - Shoutao Zhang
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China; Henan Key Laboratory of Bioactive Macromolecules, Zhengzhou, Henan, China.
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Issigonis M, Newmark PA. From worm to germ: Germ cell development and regeneration in planarians. Curr Top Dev Biol 2019; 135:127-153. [DOI: 10.1016/bs.ctdb.2019.04.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Schmidt D, Reuter H, Hüttner K, Ruhe L, Rabert F, Seebeck F, Irimia M, Solana J, Bartscherer K. The Integrator complex regulates differential snRNA processing and fate of adult stem cells in the highly regenerative planarian Schmidtea mediterranea. PLoS Genet 2018; 14:e1007828. [PMID: 30557303 PMCID: PMC6312358 DOI: 10.1371/journal.pgen.1007828] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 12/31/2018] [Accepted: 11/12/2018] [Indexed: 02/07/2023] Open
Abstract
In multicellular organisms, cell type diversity and fate depend on specific sets of transcript isoforms generated by post-transcriptional RNA processing. Here, we used Schmidtea mediterranea, a flatworm with extraordinary regenerative abilities and a large pool of adult stem cells, as an in vivo model to study the role of Uridyl-rich small nuclear RNAs (UsnRNAs), which participate in multiple RNA processing reactions including splicing, in stem cell regulation. We characterized the planarian UsnRNA repertoire, identified stem cell-enriched variants and obtained strong evidence for an increased rate of UsnRNA 3'-processing in stem cells compared to their differentiated counterparts. Consistently, components of the Integrator complex showed stem cell-enriched expression and their depletion by RNAi disrupted UsnRNA processing resulting in global changes of splicing patterns and reduced processing of histone mRNAs. Interestingly, loss of Integrator complex function disrupted both stem cell maintenance and regeneration of tissues. Our data show that the function of the Integrator complex in UsnRNA 3'-processing is conserved in planarians and essential for maintaining their stem cell pool. We propose that cell type-specific modulation of UsnRNA composition and maturation contributes to in vivo cell fate choices, such as stem cell self-renewal in planarians.
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Affiliation(s)
- David Schmidt
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
- * E-mail: (DS); (KB)
| | - Hanna Reuter
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
| | - Katja Hüttner
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
| | - Larissa Ruhe
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
| | - Franziska Rabert
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
| | - Florian Seebeck
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
| | - Manuel Irimia
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
| | - Jordi Solana
- Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Kerstin Bartscherer
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
- Hubrecht Institute for Developmental Biology and Stem Cell Research, CT Utrecht, The Netherlands
- * E-mail: (DS); (KB)
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Mihaylova Y, Abnave P, Kao D, Hughes S, Lai A, Jaber-Hijazi F, Kosaka N, Aboobaker AA. Conservation of epigenetic regulation by the MLL3/4 tumour suppressor in planarian pluripotent stem cells. Nat Commun 2018; 9:3633. [PMID: 30194301 PMCID: PMC6128892 DOI: 10.1038/s41467-018-06092-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 08/13/2018] [Indexed: 12/18/2022] Open
Abstract
Currently, little is known about the evolution of epigenetic regulation in animal stem cells. Here we demonstrate, using the planarian stem cell system to investigate the role of the COMPASS family of MLL3/4 histone methyltransferases that their function as tumor suppressors in mammalian stem cells is conserved over a long evolutionary distance. To investigate the potential conservation of a genome-wide epigenetic regulatory program in animal stem cells, we assess the effects of Mll3/4 loss of function by performing RNA-seq and ChIP-seq on the G2/M planarian stem cell population, part of which contributes to the formation of outgrowths. We find many oncogenes and tumor suppressors among the affected genes that are likely candidates for mediating MLL3/4 tumor suppression function. Our work demonstrates conservation of an important epigenetic regulatory program in animals and highlights the utility of the planarian model system for studying epigenetic regulation.
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Affiliation(s)
- Yuliana Mihaylova
- Department of Zoology, Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK
| | - Prasad Abnave
- Department of Zoology, Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK
| | - Damian Kao
- Department of Zoology, Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK
| | - Samantha Hughes
- HAN University of Applied Sciences, Institute of Applied Sciences, Laan van Scheut 2, 6525EM, Nijmegen, The Netherlands
| | - Alvina Lai
- Department of Zoology, Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK
| | - Farah Jaber-Hijazi
- Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow, G61 1BD, UK
| | - Nobuyoshi Kosaka
- Department of Zoology, Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK
| | - A Aziz Aboobaker
- Department of Zoology, Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK.
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Dattani A, Kao D, Mihaylova Y, Abnave P, Hughes S, Lai A, Sahu S, Aboobaker AA. Epigenetic analyses of planarian stem cells demonstrate conservation of bivalent histone modifications in animal stem cells. Genome Res 2018; 28:1543-1554. [PMID: 30143598 PMCID: PMC6169894 DOI: 10.1101/gr.239848.118] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/16/2018] [Indexed: 12/14/2022]
Abstract
Planarian flatworms have an indefinite capacity to regenerate missing or damaged body parts owing to a population of pluripotent adult stems cells called neoblasts (NBs). Currently, little is known about the importance of the epigenetic status of NBs and how histone modifications regulate homeostasis and cellular differentiation. We have developed an improved and optimized ChIP-seq protocol for NBs in Schmidtea mediterranea and have generated genome-wide profiles for the active marks H3K4me3 and H3K36me3, and suppressive marks H3K4me1 and H3K27me3. The genome-wide profiles of these marks were found to correlate well with NB gene expression profiles. We found that genes with little transcriptional activity in the NB compartment but which switch on in post-mitotic progeny during differentiation are bivalent, being marked by both H3K4me3 and H3K27me3 at promoter regions. In further support of this hypothesis, bivalent genes also have a high level of paused RNA Polymerase II at the promoter-proximal region. Overall, this study confirms that epigenetic control is important for the maintenance of a NB transcriptional program and makes a case for bivalent promoters as a conserved feature of animal stem cells and not a vertebrate-specific innovation. By establishing a robust ChIP-seq protocol and analysis methodology, we further promote planarians as a promising model system to investigate histone modification–mediated regulation of stem cell function and differentiation.
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Affiliation(s)
- Anish Dattani
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
| | - Damian Kao
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
| | - Yuliana Mihaylova
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
| | - Prasad Abnave
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
| | - Samantha Hughes
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
| | - Alvina Lai
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
| | - Sounak Sahu
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
| | - A Aziz Aboobaker
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
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Swapna LS, Molinaro AM, Lindsay-Mosher N, Pearson BJ, Parkinson J. Comparative transcriptomic analyses and single-cell RNA sequencing of the freshwater planarian Schmidtea mediterranea identify major cell types and pathway conservation. Genome Biol 2018; 19:124. [PMID: 30143032 PMCID: PMC6109357 DOI: 10.1186/s13059-018-1498-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 08/01/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND In the Lophotrochozoa/Spiralia superphylum, few organisms have as high a capacity for rapid testing of gene function and single-cell transcriptomics as the freshwater planaria. The species Schmidtea mediterranea in particular has become a powerful model to use in studying adult stem cell biology and mechanisms of regeneration. Despite this, systematic attempts to define gene complements and their annotations are lacking, restricting comparative analyses that detail the conservation of biochemical pathways and identify lineage-specific innovations. RESULTS In this study we compare several transcriptomes and define a robust set of 35,232 transcripts. From this, we perform systematic functional annotations and undertake a genome-scale metabolic reconstruction for S. mediterranea. Cross-species comparisons of gene content identify conserved, lineage-specific, and expanded gene families, which may contribute to the regenerative properties of planarians. In particular, we find that the TRAF gene family has been greatly expanded in planarians. We further provide a single-cell RNA sequencing analysis of 2000 cells, revealing both known and novel cell types defined by unique signatures of gene expression. Among these are a novel mesenchymal cell population as well as a cell type involved in eye regeneration. Integration of our metabolic reconstruction further reveals the extent to which given cell types have adapted energy and nucleotide biosynthetic pathways to support their specialized roles. CONCLUSIONS In general, S. mediterranea displays a high level of gene and pathway conservation compared with other model systems, rendering it a viable model to study the roles of these pathways in stem cell biology and regeneration.
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Affiliation(s)
| | - Alyssa M Molinaro
- Hospital for Sick Children, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Nicole Lindsay-Mosher
- Hospital for Sick Children, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Bret J Pearson
- Hospital for Sick Children, Toronto, ON, Canada. .,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada. .,Ontario Institute for Cancer Research, Toronto, ON, Canada.
| | - John Parkinson
- Hospital for Sick Children, Toronto, ON, Canada. .,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada. .,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
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Ernst EH, Nielsen J, Ipsen MB, Villesen P, Lykke-Hartmann K. Transcriptome Analysis of Long Non-coding RNAs and Genes Encoding Paraspeckle Proteins During Human Ovarian Follicle Development. Front Cell Dev Biol 2018; 6:78. [PMID: 30087896 PMCID: PMC6066568 DOI: 10.3389/fcell.2018.00078] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 07/02/2018] [Indexed: 12/11/2022] Open
Abstract
Emerging evidence indicated that many long non-coding (lnc)RNAs function in multiple biological processes and dysregulation of their expression can cause diseases. Most regulatory lncRNAs interact with biological macromolecules such as DNA, RNA, and protein. LncRNAs regulate gene expression through epigenetic modification, transcription, and posttranscription, through DNA methylation, histone modification, and chromatin remodeling. Interestingly, differential lncRNA expression profiles in human oocytes and cumulus cells was recently assessed, however, lncRNAs in human follicle development has not previously been described. In this study, transcriptome dynamics in human primordial, primary and small antral follicles were interrogated and revealed information of lncRNA genes. It is known that some lncRNAs form a complex with paraspeckle proteins and therefore, we extended our transcriptional analysis to include genes encoding paraspeckle proteins. Primordial, primary follicles and small antral follicles was isolated using laser capture micro-dissection from ovarian tissue donated by three women having ovarian tissue cryopreserved before chemotherapy. After RN sequencing, a bioinformatic class comparison was performed and primordial, primary and small antral follicles were found to express several lncRNA and genes encoding paraspeckle proteins. Of particular interest, we detected the lncRNAs XIST, NEAT1, NEAT2 (MALAT1), and GAS5. Moreover, we noted a high expression of FUS, TAF15, and EWS components of the paraspeckles, proteins that belong to the FET (previously TET) family of RNA-binding proteins and are implicated in central cellular processes such as regulation of gene expression, maintenance of genomic integrity, and mRNA/microRNA processing. We also interrogated the intra-ovarian localization of the FUS, TAF15, and EWS proteins using immunofluorescence. The presence and the dynamics of genes that encode lncRNA and paraspeckle proteins may suggest that these may mediate functions in the cyclic recruitment and differentiation of human follicles and could participate in biological processes known to be associated with lncRNAs and paraspeckle proteins, such as gene expression control, scaffold formation and epigenetic control through human follicle development. This comprehensive transcriptome analysis of lncRNAs and genes encoding paraspeckle proteins expressed in human follicles could potentially provide biomarkers of oocyte quality for the development of non-invasive tests to identify embryos with high developmental potential.
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Affiliation(s)
- Emil H. Ernst
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Julie Nielsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Malene B. Ipsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Palle Villesen
- Bioinformatic Research Centre, Aarhus University, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Karin Lykke-Hartmann
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark
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Post-transcriptional regulation in planarian stem cells. Semin Cell Dev Biol 2018; 87:69-78. [PMID: 29870807 DOI: 10.1016/j.semcdb.2018.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 05/11/2018] [Accepted: 05/14/2018] [Indexed: 12/17/2022]
Abstract
Planarians are known for their immense regenerative abilities. A pluripotent stem cell population provides the cellular source for this process, as well as for the homeostatic cell turnover of the animals. These stem cells, known as neoblasts, present striking similarities at the morphological and molecular level to germ cells, but however, give rise to somatic tissue. Many RNA binding proteins known to be important for germ cell biology are also required for neoblast function, highlighting the importance of post-transcriptional regulation for stem cell control. Many of its aspects, including alternative splicing, alternative polyadenylation, translational control and mRNA deadenylation, as well as small RNAs such as microRNAs and piRNA are critical for stem cells. Their inhibition often abrogates both regeneration and cell turnover, resulting in lethality. Some of aspects of post-transcriptional regulation are conserved from planarian to mammalian stem cells.
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Lindsay-Mosher N, Pearson BJ. The true colours of the flatworm: Mechanisms of pigment biosynthesis and pigment cell lineage development in planarians. Semin Cell Dev Biol 2018; 87:37-44. [PMID: 29758350 DOI: 10.1016/j.semcdb.2018.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/07/2018] [Accepted: 05/10/2018] [Indexed: 11/28/2022]
Abstract
Pigment cells serve a variety of important uses across the animal kingdom, and in many species can change and regenerate throughout the lifetime of the organism. The functions of these cells, as well as their origins in both embryonic development and adult regeneration, are not fully understood. Here, we review advances in the study of pigment cells in the freshwater planarian, a model system for stem cell biology and regeneration. Freshwater planarians produce at least three pigment types to generate brown eye and body colouration: melanin, porphyrin, and ommochrome. The body pigments of planarians are produced and contained by a specialized, highly dendritic cell type located in the subepidermal parenchymal space. This cell type is specifically ablated following intense light exposure, a characteristic which has been exploited to discover the gene expression and regeneration of planarian pigment cells. Regenerating pigment cells progress through an immature state marked by upregulation of pigment synthesis genes before differentiating into mature pigment cells; these two states are dynamically regulated in homeostasis to maintain constant body pigmentation. The transcription factors Albino, FoxF-1, and Ets-1, as well as an FGFR-like molecule, are required for proper maintenance of the pigment lineage in both regeneration and homeostasis. These discoveries set the stage for research into external signals that regulate the pigment lineage, as well as possible functions for pigment cells in planarians, including the extra-ocular light response. These insights will address outstanding questions about the evolutionarily-conserved biology of pigment cells.
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Affiliation(s)
- Nicole Lindsay-Mosher
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, M5G 0A4, Canada
| | - Bret J Pearson
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, M5G 0A4, Canada; Ontario Institute for Cancer Research, Toronto, ON, M5G 0A4, Canada.
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46
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The role of the EGFR signaling pathway in stem cell differentiation during planarian regeneration and homeostasis. Semin Cell Dev Biol 2018; 87:45-57. [PMID: 29775660 DOI: 10.1016/j.semcdb.2018.05.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/07/2018] [Accepted: 05/14/2018] [Indexed: 12/25/2022]
Abstract
Cell signaling is essential for cells to adequately respond to their environment. One of the most evolutionarily conserved signaling pathways is that of the epidermal growth factor receptor (EGFR). Transmembrane receptors with intracellular tyrosine kinase activity are activated by the binding of their corresponding ligands. This in turn activates a wide variety of intracellular cascades and induces the up- or downregulation of target genes, leading to a specific cellular response. Freshwater planarians are an excellent model in which to study the role of cell signaling in the context of stem-cell based regeneration. Owing to the presence of a population of pluripotent stem cells called neoblasts, these animals can regenerate the entire organism from a tiny piece of the body. Here, we review the current state of knowledge of the planarian EGFR pathway. We describe the main components of the pathway and their functions in other animals, and focus in particular on receptors and ligands identified in the planarian Schmidtea mediterranea. Moreover, we summarize current data on the function of some of these components during planarian regeneration and homeostasis. We hypothesize that the EGFR pathway may act as a key regulator of the terminal differentiation of distinct populations of lineage-committed progenitors.
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47
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Tran TA, Gentile L. A lineage CLOUD for neoblasts. Semin Cell Dev Biol 2018; 87:22-29. [PMID: 29727726 DOI: 10.1016/j.semcdb.2018.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/10/2018] [Accepted: 04/25/2018] [Indexed: 12/18/2022]
Abstract
In planarians, pluripotency can be studied in vivo in the adult animal, making these animals a unique model system where pluripotency-based regeneration (PBR)-and its therapeutic potential-can be investigated. This review focuses on recent findings to build a cloud model of fate restriction likelihood for planarian stem and progenitor cells. Recently, a computational approach based on functional and molecular profiling at the single cell level was proposed for human hematopoietic stem cells. Based on data generated both in vivo and ex vivo, we hypothesized that planarian stem cells could acquire multiple direction lineage biases, following a "badlands" landscape. Instead of a discrete tree-like hierarchy, where the potency of stem/progenitor cells reduces stepwise, we propose a Continuum of LOw-primed UnDifferentiated Planarian Stem/Progenitor Cells (CLOUD-PSPCs). Every subclass of neoblast/progenitor cells is a cloud of likelihood, as the single cell transcriptomics data indicate. The CLOUD-HSPCs concept was substantiated by in vitro data from cell culture; therefore, to confirm the CLOUD-PSPCs model, the planarian community needs to develop new tools, like live cell tracking. Future studies will allow a deeper understanding of PBR in planarian, and the possible implications for regenerative therapies in human.
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Affiliation(s)
- Thao Anh Tran
- Pluripotency and Regeneration Group, Fraunhofer Institute for Biomedical Engineering, Joseph-von-Fraunhofer-Weg, 1, 66280, Sulzbach, Germany
| | - Luca Gentile
- Pluripotency and Regeneration Group, Fraunhofer Institute for Biomedical Engineering, Joseph-von-Fraunhofer-Weg, 1, 66280, Sulzbach, Germany; Planarian Stem Cell Laboratory, Max Planck Institute for Molecular Biomedicine, von-Esmarch-str. 54, 48149, Münster, Germany; Hasselt University - Campus Diepenbeek, Agoralaan building D, 3590, Diepenbeek, Belgium.
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48
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Fincher CT, Wurtzel O, de Hoog T, Kravarik KM, Reddien PW. Cell type transcriptome atlas for the planarian Schmidtea mediterranea. Science 2018; 360:science.aaq1736. [PMID: 29674431 DOI: 10.1126/science.aaq1736] [Citation(s) in RCA: 268] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 04/05/2018] [Indexed: 12/31/2022]
Abstract
The transcriptome of a cell dictates its unique cell type biology. We used single-cell RNA sequencing to determine the transcriptomes for essentially every cell type of a complete animal: the regenerative planarian Schmidtea mediterranea. Planarians contain a diverse array of cell types, possess lineage progenitors for differentiated cells (including pluripotent stem cells), and constitutively express positional information, making them ideal for this undertaking. We generated data for 66,783 cells, defining transcriptomes for known and many previously unknown planarian cell types and for putative transition states between stem and differentiated cells. We also uncovered regionally expressed genes in muscle, which harbors positional information. Identifying the transcriptomes for potentially all cell types for many organisms should be readily attainable and represents a powerful approach to metazoan biology.
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Affiliation(s)
- Christopher T Fincher
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Omri Wurtzel
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Thom de Hoog
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kellie M Kravarik
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Peter W Reddien
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA. .,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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49
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Neoblast-enriched zinc finger protein FIR1 triggers local proliferation during planarian regeneration. Protein Cell 2018; 10:43-59. [PMID: 29557542 PMCID: PMC6321819 DOI: 10.1007/s13238-018-0512-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 01/09/2018] [Indexed: 11/30/2022] Open
Abstract
Regeneration, relying mainly on resident adult stem cells, is widespread. However, the mechanism by which stem cells initiate proliferation during this process in vivo is unclear. Using planarian as a model, we screened 46 transcripts showing potential function in the regulation of local stem cell proliferation following 48 h regeneration. By analyzing the regeneration defects and the mitotic activity of animals under administration of RNA interference (RNAi), we identified factor for initiating regeneration 1 (Fir1) required for local proliferation. Our findings reveal that Fir1, enriched in neoblasts, promotes planarian regeneration in any tissue-missing context. Further, we demonstrate that DIS3 like 3′-5′ exoribonuclease 2 (Dis3l2) is required for Fir1 phenotype. Besides, RNAi knockdown of Fir1 causes a decrease of neoblast wound response genes following amputation. These findings suggest that Fir1 recognizes regenerative signals and promotes DIS3L2 proteins to trigger neoblast proliferation following amputation and provide a mechanism critical for stem cell response to injury.
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Rink JC. Stem Cells, Patterning and Regeneration in Planarians: Self-Organization at the Organismal Scale. Methods Mol Biol 2018; 1774:57-172. [PMID: 29916155 DOI: 10.1007/978-1-4939-7802-1_2] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The establishment of size and shape remains a fundamental challenge in biological research that planarian flatworms uniquely epitomize. Planarians can regenerate complete and perfectly proportioned animals from tiny and arbitrarily shaped tissue pieces; they continuously renew all organismal cell types from abundant pluripotent stem cells, yet maintain shape and anatomy in the face of constant turnover; they grow when feeding and literally degrow when starving, while scaling form and function over as much as a 40-fold range in body length or an 800-fold change in total cell numbers. This review provides a broad overview of the current understanding of the planarian stem cell system, the mechanisms that pattern the planarian body plan and how the interplay between patterning signals and cell fate choices orchestrates regeneration. What emerges is a conceptual framework for the maintenance and regeneration of the planarian body plan on basis of the interplay between pluripotent stem cells and self-organizing patterns and further, the general utility of planarians as model system for the mechanistic basis of size and shape.
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Affiliation(s)
- Jochen C Rink
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
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