scholarly journals Smed-egfr-4 is required for planarian eye regeneration

2018 ◽  
Author(s):  
Elena Emili ◽  
Maclà Esteve Pallarès ◽  
Rafael Romero ◽  
Francesc Cebrlà
Keyword(s):  
Stem Cells ◽  
Progenitor Cells ◽  
Pluripotent Stem Cells ◽  
Growth Factor Receptor ◽  
Cell Types ◽  
Whole Body ◽  
Pigment Cells ◽  
Mature Cell ◽  
General Role ◽  
Photoreceptor Neurons

ABSTRACTPlanarians are amazing animals that can regenerate a whole body from a tiny piece of them thanks to their pluripotent stem cells, the neoblasts. Planarian neoblasts include both pluripotent stem cells and specialized lineage-committed progenitors that give rise to all the mature cell types during regeneration and homeostatic cell turnover in these plastic animals. Little is known, however, about the mechanisms that regulate neoblast differentiation. Recently, it has been shown that Smed-egfr-1, a homologue of the epidermal growth factor receptor (EGFR) family is required for the final differentiation of the gut progenitors into mature cells but not for their specification. As planarians have several EGFR homologues it has been proposed that they could have diverged functionally to regulate the differentiation of the different cell types found in these animals. Here, we report on the function of Smed-egfr-4 on eye regeneration. The silencing of this gene by RNAi results in animals regenerating smaller eyes compared to controls. The numbers of both eye mature cell types, photoreceptor neurons and eye-cup pigment cells, are significantly decreased in the Smed-egfr-4(RNAi) animals. In contrast, the number of eye progenitor cells expressing the specific markers Smed-ovo and Smed-sp6-9 is increased. These results suggest that Smed-egfr-4 would be required not for the specification of eye progenitor cells but rather for their final differentiation and support the idea that in planarians the EGFR pathway could play a general role regulating the differentiation of lineage-committed progenitors.

scholarly journals Smed-egfr-4 is required for planarian eye regeneration

2019 ◽  
Vol 63 (1-2) ◽  
pp. 9-15 ◽  
Author(s):  
Elena Emili ◽  
Macià Esteve Pallarès ◽  
Rafael Romero ◽  
Francesc Cebrià
Keyword(s):  
Stem Cells ◽  
Progenitor Cells ◽  
Pluripotent Stem Cells ◽  
Growth Factor Receptor ◽  
Cell Types ◽  
Entire Body ◽  
General Role ◽  
Distinct Cell ◽  
Egfr Family ◽  
Photoreceptor Neurons

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.

scholarly journals Adaptation to oxygen deprivation in cultures of human pluripotent stem cells, endothelial progenitor cells, and umbilical vein endothelial cells

2010 ◽  
Vol 298 (6) ◽  
pp. C1527-C1537 ◽  
Author(s):  
Hasan Erbil Abaci ◽  
Rachel Truitt ◽  
Eli Luong ◽  
German Drazer ◽  
Sharon Gerecht
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Oxygen Consumption ◽  
Progenitor Cells ◽  
Pluripotent Stem Cells ◽  
Cell Types ◽  
Cellular Responses ◽  
Glut 1 ◽  
Lower Oxygen ◽  
Oxygen Tensions

Hypoxia plays an important role in vascular development through hypoxia-inducible factor-1α (HIF-1α) accumulation and downstream pathway activation. We sought to explore the in vitro response of cultures of human embryonic stem cells (hESCs), induced pluripotent stem cells (iPSCs), human endothelial progenitor cells (hEPCs), and human umbilical cord vein endothelial cells (HUVECs) to normoxic and hypoxic oxygen tensions. We first measured dissolved oxygen (DO) in the media of adherent cultures in atmospheric (21% O2), physiological (5% O2), and hypoxic oxygen conditions (1% O2). In cultures of both hEPCs and HUVECs, lower oxygen consumption was observed when cultured in 1% O2. At each oxygen tension, feeder-free cultured hESCs and iPSCs were found to consume comparable amounts of oxygen. Transport analysis revealed that the oxygen uptake rate (OUR) of hESCs and iPSCs decreased distinctly as DO availability decreased, whereas the OUR of all cell types was found to be low when cultured in 1% O2, demonstrating cell adaptation to lower oxygen tensions by limiting oxygen consumption. Next, we examined HIF-1α accumulation and the expression of target genes, including VEGF and angiopoietins ( ANGPT; angiogenic response), GLUT-1 (glucose transport), BNIP3, and BNIP3L (autophagy and apoptosis). Accumulations of HIF-1α were detected in all four cell lines cultured in 1% O2. Corresponding upregulation of VEGF, ANGPT2, and GLUT-1 was observed in response to HIF-1α accumulation, whereas upregulation of ANGPT1 was detected only in hESCs and iPSCs. Upregulation of BNIP3 and BNIP3L was detected in all cells after 24-h culture in hypoxic conditions, whereas apoptosis was not detectable using flow cytometry analysis, suggesting that BNIP3 and BNIP3L can lead to cell autophagy rather than apoptosis. These results demonstrate adaptation of all cell types to hypoxia but different cellular responses, suggesting that continuous measurements and control over oxygen environments will enable us to guide cellular responses.

scholarly journals The genetics of induced pluripotency

Reproduction ◽  
2010 ◽  
Vol 139 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Amy Ralston ◽  
Janet Rossant
Keyword(s):  
Stem Cells ◽  
Pluripotent Stem Cells ◽  
Molecular Level ◽  
Embryonic Stem ◽  
Cell Types ◽  
Therapeutic Benefit ◽  
Mature Cell ◽  
Developmental Potential ◽  
Induced Pluripotency ◽  
Induced Pluripotent

The flurry of recent publications regarding reprogramming of mature cell types to induced pluripotent stem cells raises the question: what exactly is pluripotency? A functional definition is provided by examination of the developmental potential of pluripotent stem cell types. Defining pluripotency at the molecular level, however, can be a greater challenge. Here, we examine the emerging list of genes associated with induced pluripotency, with particular attention to their functional requirement in the mouse embryo. Knowledge of the requirement for these genes in the embryo and in embryonic stem cells will advance our understanding of how to reverse the developmental clock for therapeutic benefit.

scholarly journals Decoding Stem Cells: An Overview on Planarian Stem Cell Heterogeneity and Lineage Progression

Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1532
Author(s):  
M. Dolores Molina ◽  
Francesc Cebrià
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Pluripotent Stem Cells ◽  
Current Knowledge ◽  
Large Population ◽  
Body Part ◽  
Cell Types ◽  
Whole Body ◽  
Unique System

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.

scholarly journals Stability of Imprinting and Differentiation Capacity in Naïve Human Cells Induced by Chemical Inhibition of CDK8 and CDK19

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 876
Author(s):  
Raquel Bernad ◽  
Cian J. Lynch ◽  
Rocio G. Urdinguio ◽  
Camille Stephan-Otto Attolini ◽  
Mario F. Fraga ◽  
...  
Keyword(s):  
Stem Cells ◽  
Pluripotent Stem Cells ◽  
Primordial Germ Cell ◽  
Normal Karyotype ◽  
Cell Types ◽  
Dna Demethylation ◽  
Starting State ◽  
Teratoma Formation

Pluripotent stem cells can be stabilized in vitro at different developmental states by the use of specific chemicals and soluble factors. The naïve and primed states are the best characterized pluripotency states. Naïve pluripotent stem cells (PSCs) correspond to the early pre-implantation blastocyst and, in mice, constitute the optimal starting state for subsequent developmental applications. However, the stabilization of human naïve PSCs remains challenging because, after short-term culture, most current methods result in karyotypic abnormalities, aberrant DNA methylation patterns, loss of imprinting and severely compromised developmental potency. We have recently developed a novel method to induce and stabilize naïve human PSCs that consists in the simple addition of a chemical inhibitor for the closely related CDK8 and CDK19 kinases (CDK8/19i). Long-term cultured CDK8/19i-naïve human PSCs preserve their normal karyotype and do not show widespread DNA demethylation. Here, we investigate the long-term stability of allele-specific methylation at imprinted loci and the differentiation potency of CDK8/19i-naïve human PSCs. We report that long-term cultured CDK8/19i-naïve human PSCs retain the imprinting profile of their parental primed cells, and imprints are further retained upon differentiation in the context of teratoma formation. We have also tested the capacity of long-term cultured CDK8/19i-naïve human PSCs to differentiate into primordial germ cell (PGC)-like cells (PGCLCs) and trophoblast stem cells (TSCs), two cell types that are accessible from the naïve state. Interestingly, long-term cultured CDK8/19i-naïve human PSCs differentiated into PGCLCs with a similar efficiency to their primed counterparts. Also, long-term cultured CDK8/19i-naïve human PSCs were able to differentiate into TSCs, a transition that was not possible for primed PSCs. We conclude that inhibition of CDK8/19 stabilizes human PSCs in a functional naïve state that preserves imprinting and potency over long-term culture.

scholarly journals Utilising Induced Pluripotent Stem Cells in Neurodegenerative Disease Research: Focus on Glia

2021 ◽  
Vol 22 (9) ◽  
pp. 4334
Author(s):  
Katrina Albert ◽  
Jonna Niskanen ◽  
Sara Kälvälä ◽  
Šárka Lehtonen
Keyword(s):  
Stem Cells ◽  
Neurodegenerative Diseases ◽  
Neurodegenerative Disease ◽  
Induced Pluripotent Stem Cells ◽  
Glial Cells ◽  
Pluripotent Stem Cells ◽  
Cell Types ◽  
Human Ipscs ◽  
Induced Pluripotent

Induced pluripotent stem cells (iPSCs) are a self-renewable pool of cells derived from an organism’s somatic cells. These can then be programmed to other cell types, including neurons. Use of iPSCs in research has been two-fold as they have been used for human disease modelling as well as for the possibility to generate new therapies. Particularly in complex human diseases, such as neurodegenerative diseases, iPSCs can give advantages over traditional animal models in that they more accurately represent the human genome. Additionally, patient-derived cells can be modified using gene editing technology and further transplanted to the brain. Glial cells have recently become important avenues of research in the field of neurodegenerative diseases, for example, in Alzheimer’s disease and Parkinson’s disease. This review focuses on using glial cells (astrocytes, microglia, and oligodendrocytes) derived from human iPSCs in order to give a better understanding of how these cells contribute to neurodegenerative disease pathology. Using glia iPSCs in in vitro cell culture, cerebral organoids, and intracranial transplantation may give us future insight into both more accurate models and disease-modifying therapies.

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