Stem Cells, Patterning and Regeneration in Planarians: Self-Organization at the Organismal Scale

Rink, Jochen C.

doi:10.1007/978-1-4939-7802-1_2

Cited by 50 publications

(55 citation statements)

References 365 publications

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“…Driven by the recent application of genomic and molecular methods, the planarian flatworm Schmidtea mediterranea has become a powerful model in which to address the molecular and cellular underpinnings of organ regeneration (9–13). In response to nearly any type of surgical amputation injury, pluripotent stem cells called neoblasts proliferate and differentiate, regenerating brain, intestine, and other tissues lost to injury (14, 15). In addition, pre-existing tissue undergoes extensive remodeling and re-scaling through both collective migration of post-mitotic cells in undamaged tissues, as well as proportional loss of cells through apoptosis (16).…”

Section: Introductionmentioning

confidence: 99%

Cell-type diversity and regionalized gene expression in the planarian intestine revealed by laser-capture microdissection transcriptome profiling

Forsthoefel

Cejda

Khan

et al. 2019

Preprint

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Organ regeneration requires precise coordination of new cell differentiation and remodeling of uninjured tissue to faithfully re-establish organ morphology and function. An atlas of gene expression and cell types in the uninjured state is therefore an essential pre-requisite for understanding how damage is repaired. Here, we use laser-capture microdissection (LCM) and RNA-Seq to define the transcriptome of the intestine of Schmidtea mediterranea, a planarian flatworm with exceptional regenerative capacity. Bioinformatic analysis of 1,844 intestine-enriched transcripts suggests extensive conservation of digestive physiology with other animals, including humans. Comparison of the intestinal transcriptome to purified absorptive intestinal cell (phagocyte) and published single-cell expression profiles confirms the identities of known intestinal cell types, and also identifies hundreds of additional transcripts with previously undetected intestinal enrichment. Furthermore, by assessing the expression patterns of 143 transcripts in situ, we discover unappreciated mediolateral regionalization of gene expression and cell-type diversity, especially among goblet cells. Demonstrating the utility of the intestinal transcriptome, we identify 22 intestine-enriched transcription factors, and find that several have distinct functional roles in the regeneration and maintenance of goblet cells. Furthermore, depletion of goblet cells inhibits planarian feeding and reduces viability. Altogether, our results show that LCM is a viable approach for assessing tissue-specific gene expression in planarians, and provide a new resource for further investigation of digestive tract regeneration, the physiological roles of intestinal cell types, and axial polarity.

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Section: Introductionmentioning

confidence: 99%

Cell-type diversity and regionalized gene expression in the planarian intestine revealed by laser-capture microdissection transcriptome profiling

Forsthoefel

Cejda

Khan

et al. 2019

Preprint

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“…Unravelling the mechanisms that regulate stem cell differentiation is crucial in order to understand the amazing regenerative capabilities of freshwater planarians, in which a population of stem cells is maintained for the entire lifespan and can be activated in response to injury or amputation. This remarkable ability makes freshwater planarians a classical model for the study of stem cell-based regeneration (for recent reviews, see Rink 2018). Planarian neoblasts are a heterogeneous cell population consisting of truly pluripotent undifferentiated stem cells, known as cNeoblasts (Wagner et al, 2011;Zeng et al, 2018), as well as specialized lineage-committed progenitors specific for distinct mature cell types (Scimone et al, 2014;Zhu and Pearson, 2016).…”

Section: Introductionmentioning

confidence: 99%

Smed-egfr-4 is required for planarian eye regeneration

Elena¹,

Pallarès²,

Romero³

et al. 2019

Int. J. Dev. Biol.

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Planarians are remarkable organisms that can regenerate their entire body from a tiny portion thereof. This capability is made possible by the persistence throughout the lifespan of these animals of a population of pluripotent stem cells known as neoblasts. Planarian neoblasts include both pluripotent stem cells and specialized lineage-committed progenitors that give rise to all mature cell types during regeneration and homeostatic cell turnover. However, little is known about the mechanisms that regulate neoblast differentiation. A recent study demonstrated that Smed-egfr-1, a homologue of the epidermal growth factor receptor (EGFR) family, is required for final differentiation, but not specification, of gut progenitor cells into mature cells. Given the expression by planarians of several EGFR homologues, it has been proposed that these homologues may have diverged functionally to regulate the differentiation of distinct cell types in these animals. In this study, we investigated the role of Smed-egfr-4 in eye regeneration. Compared with controls, animals in which this gene was silenced by RNA interference (RNAi) regenerated smaller eyes. Moreover, the numbers of both mature eye cell types, photoreceptor neurons and cells of the pigment cup, were significantly reduced in Smed-egfr-4(RNAi) animals. By contrast, these animals exhibited an increase in the numbers of eye progenitor cells expressing the specific markers Smed-ovo and Smed-sp6-9. These results suggest that Smed-egfr-4 is required not for the specification of eye progenitor cells but for their final differentiation, and support the view that in planarians the EGFR pathway might play a general role in regulating the differentiation of lineage-committed progenitors.

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“…Genes of interest were amplified from cDNA with gene‐specific primers containing overhangs homologous to the pPR‐T4P vector and cloned using ligation‐independent cloning (Table S3) .…”

Section: Methodsmentioning

confidence: 99%

A modular laboratory course using planarians to study genes involved in tissue regeneration

Ochoa

Dores

Allen

et al. 2019

Biochem Molecular Bio Educ

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Undergraduate research experiences are excellent opportunities to engage students in science alongside experienced scientists, but at large institutions, it is challenging to accommodate all students. To address and engage a larger number of students, we developed a modular laboratory course based on the course-based undergraduate research experiences model. This new course was integrated with the scientific aims of a research laboratory studying the cellular and molecular mechanisms underlying tissue regeneration in planarians. In this course, students were asked to identify genes with roles in planarian biology. Students analyzed and cloned an assigned gene, determined its expression pattern in situ and examined its function in regeneration. Additionally, we developed critical thinking and scientific communication skills by incorporating activities focused on critical concepts. Students obtained high quality primary data and were successful in completing and mastering the course learning outcomes. They benefitted by developing basic research skills, learning to perform, trouble-shooting experiments, reading and critically analyzing primary literature, and using the information to defend and explain their experimental results. Through this course, students also increased their confidence and ability to perform independent scientific research. The course was designed to make it accessible to the community to implement and adapt as appropriate in diverse institutions. Biochemistry and Molecular Biology Education Riboprobe Synthesis and Whole-Mount in situ HybridizationAntisense RNA probes were produced [23]. Briefly, DNA templates were PCR amplified from cDNA clones in pPR-T4P plasmid vectors. Antisense riboprobes labeled with digoxigenin were synthesized at 37 C. Probes were purified via ethanol precipitation and whole-mount in situ hybridization was performed manually [24] (see step by step protocol) with some modifications to fit the classroom settings. Planarians were sacrificed using a 5% N-acetyl cysteine solution prior to 548 An Undergraduate Laboratory Course Studying Planarian Regeneration

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Stem Cells, Patterning and Regeneration in Planarians: Self-Organization at the Organismal Scale

Cited by 50 publications

References 365 publications

Cell-type diversity and regionalized gene expression in the planarian intestine revealed by laser-capture microdissection transcriptome profiling

Cell-type diversity and regionalized gene expression in the planarian intestine revealed by laser-capture microdissection transcriptome profiling

Smed-egfr-4 is required for planarian eye regeneration

A modular laboratory course using planarians to study genes involved in tissue regeneration

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