scholarly journals A pluri- és multipotencia határán: a ganglionléc őssejtjei

2015 ◽  
Vol 156 (42) ◽  
pp. 1683-1694
Author(s):  
Gyöngyi Kudlik ◽  
Zsolt Matula ◽  
Tamás Kovács ◽  
S. Veronika Urbán ◽  
Ferenc Uher

The neural crest is a transient, multipotent, migratory cell population that is unique to vertebrate embryos and gives rise to many derivatives, ranging from the neuronal and glial components of the peripheral nervous system to the ectomesenchymal derivatives of the craniofacial area and pigment cells in the skin. Intriguingly, the neural crest derived stem cells are not only present in the embryonic neural crest, but also in their target tissues in the fetus and adult. These postmigratory stem cells, at least partially, resemble their multipotency. Moreover, fully differentiated neural crest-derived cells such as Schwann cells and melanocytes are able to dedifferentiate into stem-like progenitors. Here the authors review current understanding of this unique plasticity and its potential application in stem cell biology as well as in regenerative medicine. Orv. Hetil., 2015, 156(42), 1683–1694.

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 301-305 ◽  
Author(s):  
A. Baroffio ◽  
E. Dupin ◽  
N.M. Le Douarin

The cephalic neural crest (NC) of vertebrate embryos yields a variety of cell types belonging to the neuronal, glial, melanocytic and mesectodermal lineages. Using clonal cultures of quail migrating cephalic NC cells, we demonstrated that neurons and glial cells of the peripheral nervous system can originate from the same progenitors as cartilage, one of the mesectodermal derivatives of the NC. Moreover, we obtained evidence that the migrating cephalic NC contains a few highly multipotent precursors that are common to neurons, glia, cartilage and pigment cells and which we interprete as representative of a stem cell population. In contrast, other NC cells, although provided with identical culture conditions, give rise to clones composed of only one or some of these cell types. These cells thus appear restricted in their developmental potentialities compared to multipotent cells. It is therefore proposed that, in vivo, the active proliferation of pluripotent NC cells during the migration process generates distinct subpopulations of cells that become progressively committed to different developmental fates.


Development ◽  
1968 ◽  
Vol 19 (2) ◽  
pp. 109-119
Author(s):  
Judith Shulman Weis

In teleost fishes, unlike many other vertebrates, the spinal cord originates as a solid structure, the neural keel, which subsequently hollows out. Unlike vertebrates in which the neural tube is formed from neural folds, and where the neural crest arises from wedge-shaped masses of tissue connecting the neural tube to the general ectoderm, teleosts do not possess a clear morphological neural crest. Initially, the dorsal surface of the keel is broadly attached to the ectoderm as described by Shepard (1961). As the neural primordia become larger and more discrete, the region of attachment narrows, and cells become loose (the ‘loose crest stage’). These cells represent the neural crest. Subsequently they begin to migrate and to differentiate into the various derivatives of neural crest. Both sensory and sympathetic neurons arise from neural crest. At the time of their migration the cells are not morphologically distinguishable.


2016 ◽  
Author(s):  
Αθανάσιος Στεργιόπουλος

Το δυναμικό και η ικανότητα αυτο-ανανέωσης και διαφοροποίησης των νευρικών βλαστικών κυττάρων (ΝΒΚ) ελέγχονται από τη δράση διαφόρων μεταγραφικών παραγόντων και πυρηνικών υποδοχέων, επηρεάζοντας μ ’αυτόν τον τρόπο την ανάπτυξη και τη λειτουργία του κεντρικού νευρικού συστήματος (ΚΝΣ). Στην παρούσα μελέτη χαρακτηρίσαμε τον ορφανό πυρηνικό υποδοχέα NR5A2 (LRH1), ως ένα νέο μόριο το οποίο κατέχει κεντρικό αναπτυξιακό ρόλο στο ΚΝΣ. Με πειράματα υπερ-έκφρασης και αποσιώπησης γονιδίων σε πρωτογενή ΝΒΚ καθώς και με ανάλυση εμβρύων ποντικών στα οποία έχει επιτραπεί η ιστο-ειδική και χρονική εξάλειψη του NR5A2, δείξαμε πως ο NR5A2 είναι ικανός να διακόπτει τον πολλαπλασιασμό των ΝΒΚ, οδηγώντας τα προς τη νευρωνική διαφοροποίηση με την παράλληλη απώλεια των αστροκυττάρων. Σε μηχανιστική βάση, ο NR5A2 ελέγχει αυτούς τους φαινοτύπους μέσω της άμεσης επίδρασής του στον γενετικό τόπο του Ink4/Arf, στο Prox1, το οποίο αποτελεί καθοδικό στόχο των προ-νευρικών γονιδίων, καθώς επίσης και στα σηματοδοτικά μονοπάτια του Notch1 και του JAK/STAT. Αντιθέτως, ο NR5A2 ρυθμίζεται ανοδικά από προ-νευρικά γονίδια και από τα Notch1 και JAK/STAT μονοπάτια. Συμπερασματικά, οι παρατηρήσεις μας προτείνουν τον NR5A2 σαν ένα νέο υποδοχέα-ρυθμιστή της ανάπτυξης του ΚΝΣ, και, σε συνδυασμό με την ανακάλυψη αγωνιστών/ανταγωνιστών του, τον καθιστούν υποψήφιο στόχο στην ανάπτυξη θεραπευτικών στρατηγικών αναγεννητικής ιατρικής του ΚΝΣ.


2015 ◽  
Author(s):  
◽  
Jason Neville Sterrenberg

The therapeutic potential of stem cells is already being harnessed in clinical trails. Of even greater therapeutic potential has been the discovery of mechanisms to reprogram differentiated cells into a pluripotent stem cell-like state known as induced pluripotent stem cells (iPSCs). Stem cell nature is governed and maintained by a hierarchy of transcription factors, the apex of which is OCT4. Although much research has elucidated the transcriptional regulation of OCT4, OCT4 regulated gene expression profiles and OCT4 transcriptional activation mechanisms in both stem cell biology and cellular reprogramming to iPSCs, the fundamental biochemistry surrounding the OCT4 transcription factor remains largely unknown. In order to analyze the biochemical relationship between HSP90 and human OCT4 we developed an exogenous active human OCT4 expression model with human OCT4 under transcriptional control of a constitutive promoter. We identified the direct interaction between HSP90 and human OCT4 despite the fact that the proteins predominantly display differential subcellular localizations. We show that HSP90 inhibition resulted in degradation of human OCT4 via the ubiquitin proteasome degradation pathway. As human OCT4 and HSP90 did not interact in the nucleus, we suggest that HSP90 functions in the cytoplasmic stabilization of human OCT4. Our analysis suggests HSP90 inhibition inhibits the transcriptional activity of human OCT4 dimers without affecting monomeric OCT4 activity. Additionally our data suggests that the HSP90 and human OCT4 complex is modulated by phosphorylation events either promoting or abrogating the interaction between HSP90 and human OCT4. Our data suggest that human OCT4 displays the characteristics describing HSP90 client proteins, therefore we identify human OCT4 as a putative HSP90 client protein. The regulation of the transcription factor OCT4 by HSP90 provides fundamental insights into the complex biochemistry of stem cell biology. This may also be suggestive that HSP90 not only regulates stem cell biology by maintaining routine cellular homeostasis but additionally through the direct regulation of pluripotency factors.


2021 ◽  
pp. 39-51
Author(s):  
Jonathan Slack

‘Personalized pluripotent stem cells’ discusses cloning and its connection to stem cell biology. Somatic cell nuclear transplantation into oocytes can make personalized pluripotent stem cells as a perfect genetic match to a specific patient that provoke no immune rejection on grafting. Because this procedure involves generation of cells but no formation of an actual cloned individual, it has become known as human therapeutic cloning. Induced pluripotent stem cells (iPS cells) are made by introducing a few specific genes into normal cells. They are also a perfect genetic match to the individual donating the normal cells and because they are easy to make are now the preferred source.


2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Fernando de Sá Silva ◽  
Paula Nascimento Almeida ◽  
João Vitor Paes Rettore ◽  
Claudinéia Pereira Maranduba ◽  
Camila Maurmann de Souza ◽  
...  

Stem cells, both embryonic and adult, due to the potential for application in tissue regeneration have been the target of interest to the world scientific community. In fact, stem cells can be considered revolutionary in the field of medicine, especially in the treatment of a wide range of human diseases. However, caution is needed in the clinical application of such cells and this is an issue that demands more studies. This paper will discuss some controversial issues of importance for achieving cell therapy safety and success. Particularly, the following aspects of stem cell biology will be presented: methods for stem cells culture, teratogenic or tumorigenic potential, cellular dose, proliferation, senescence, karyotyping, and immunosuppressive activity.


Hematology ◽  
2003 ◽  
Vol 2003 (1) ◽  
pp. 398-418 ◽  
Author(s):  
George Q. Daley ◽  
Margaret A. Goodell ◽  
Evan Y. Snyder

Abstract Studies of the regenerating hematopoietic system have led to the definition of many of the fundamental principles of stem cell biology. Therapies based on a range of tissue stem cells have been widely touted as a new treatment modality, presaging an emerging new specialty called regenerative medicine that promises to harness stem cells from embryonic and somatic sources to provide replacement cell therapies for genetic, malignant, and degenerative conditions. Insights borne from stem cell biology also portend development of protein and small molecule therapeutics that act on endogenous stem cells to promote repair and regeneration. Much of the newfound enthusiasm for regenerative medicine stems from the hope that advances in the laboratory will be followed soon thereafter by breakthrough treatments in the clinic. But how does one sort through the hype to judge the true promise? Are stem cell biologists and the media building expectations that cannot be met? Which diseases can be treated, and when can we expect success? In this review, we outline the realms of investigation that are capturing the most attention, and consider the current state of scientific understanding and controversy regarding the properties of embryonic and somatic (adult) stem cells. Our objective is to provide a framework for appreciating the promise while at the same time understanding the challenges behind translating fundamental stem cell biology into novel clinical therapies.


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