scholarly journals A somatic piRNA pathway regulates epithelial-to-mesenchymal transition of chick neural crest cells

2021 ◽  
Author(s):  
Riley Galton ◽  
Katalin Fejes-Toth ◽  
Marianne E. Bronner
Keyword(s):  
Neural Crest ◽  
Neural Tube ◽  
Epithelial To Mesenchymal Transition ◽  
Embryonic Stem ◽  
Neural Crest Cells ◽  
Stem Cell Population ◽  
Small Rna Sequencing ◽  
Mesenchymal Transition ◽  
Sox2 Expression ◽  
Pirna Pathway

AbstractIn the metazoan germline, Piwi proteins play an essential regulatory role in maintenance of stemness and self-renewal by piRNA-mediated repression of transposable elements. To date, the activity of Piwi proteins and the piRNA pathway in vertebrates was believed to be confined to the gonads. Our results reveal expression of Piwil1 in a vertebrate somatic cell type, the neural crest–a migratory embryonic stem cell population. We show that Piwil1 is expressed at low levels throughout chick neural crest development, peaking just before neural crest cells undergo an epithelial-to-mesenchymal transition to leave the neural tube and migrate into the periphery. Importantly, loss of Piwil1 impedes neural crest emigration. Small RNA sequencing reveals somatic piRNAs with sequence signatures of an active ping pong loop. Coupled with Piwil1 knockout RNA-seq, our data suggest that Piwil1 regulates expression of the transposon derived gene ERNI in the chick dorsal neural tube, which in turn suppresses Sox2 expression to precisely control the timing of neural crest specification and emigration. Our work provides mechanistic insight into a novel function of the piRNA pathway as a regulator of somatic development in vertebrates.

scholarly journals Sip1 mediates an E-cadherin-to-N-cadherin switch during cranial neural crest EMT

2013 ◽  
Vol 203 (5) ◽  
pp. 835-847 ◽  
Author(s):  
Crystal D. Rogers ◽  
Ankur Saxena ◽  
Marianne E. Bronner
Keyword(s):  
Neural Crest ◽  
Neural Tube ◽  
Molecular Mechanisms ◽  
Epithelial To Mesenchymal Transition ◽  
Critical Role ◽  
Embryonic Stem ◽  
Neural Crest Cell ◽  
Stem Cell Population ◽  
Mesenchymal Transition ◽  
E Cadherin

The neural crest, an embryonic stem cell population, initially resides within the dorsal neural tube but subsequently undergoes an epithelial-to-mesenchymal transition (EMT) to commence migration. Although neural crest and cancer EMTs are morphologically similar, little is known regarding conservation of their underlying molecular mechanisms. We report that Sip1, which is involved in cancer EMT, plays a critical role in promoting the neural crest cell transition to a mesenchymal state. Sip1 transcripts are expressed in premigratory/migrating crest cells. After Sip1 loss, the neural crest specifier gene FoxD3 was abnormally retained in the dorsal neuroepithelium, whereas Sox10, which is normally required for emigration, was diminished. Subsequently, clumps of adherent neural crest cells remained adjacent to the neural tube and aberrantly expressed E-cadherin while lacking N-cadherin. These findings demonstrate two distinct phases of neural crest EMT, detachment and mesenchymalization, with the latter involving a novel requirement for Sip1 in regulation of cadherin expression during completion of neural crest EMT.

scholarly journals Draxin acts as a molecular rheostat of canonical Wnt signaling to control cranial neural crest EMT

2018 ◽  
Vol 217 (10) ◽  
pp. 3683-3697 ◽  
Author(s):  
Erica J. Hutchins ◽  
Marianne E. Bronner
Keyword(s):  
Wnt Signaling ◽  
Neural Crest ◽  
Neural Tube ◽  
Epithelial To Mesenchymal Transition ◽  
Cranial Neural Crest ◽  
Canonical Wnt Signaling ◽  
Mesenchymal Transition ◽  
Molecular Rheostat ◽  
Timing Of Initiation ◽  
Canonical Wnt

Neural crest cells undergo a spatiotemporally regulated epithelial-to-mesenchymal transition (EMT) that proceeds head to tailward to exit from the neural tube. In this study, we show that the secreted molecule Draxin is expressed in a transient rostrocaudal wave that mirrors this emigration pattern, initiating after neural crest specification and being down-regulated just before delamination. Functional experiments reveal that Draxin regulates the timing of cranial neural crest EMT by transiently inhibiting canonical Wnt signaling. Ectopic maintenance of Draxin in the cranial neural tube blocks full EMT; while cells delaminate, they fail to become mesenchymal and migratory. Loss of Draxin results in premature delamination but also in failure to mesenchymalize. These results suggest that a pulse of intermediate Wnt signaling triggers EMT and is necessary for its completion. Taken together, these data show that transient secreted Draxin mediates proper levels of canonical Wnt signaling required to regulate the precise timing of initiation and completion of cranial neural crest EMT.

Mechanisms of Neural Crest Migration

2018 ◽  
Vol 52 (1) ◽  
pp. 43-63 ◽  
Author(s):  
András Szabó ◽  
Roberto Mayor
Keyword(s):  
Neural Crest ◽  
Cell Population ◽  
Epithelial To Mesenchymal Transition ◽  
Neural Crest Cells ◽  
Cell Types ◽  
Embryonic Cell ◽  
Mesenchymal Transition ◽  
Chain Migration ◽  
Mass Migration ◽  
Neural Crest Migration

Neural crest cells are a transient embryonic cell population that migrate collectively to various locations throughout the embryo to contribute a number of cell types to several organs. After induction, the neural crest delaminates and undergoes an epithelial-to-mesenchymal transition before migrating through intricate yet characteristic paths. The neural crest exhibits a variety of migratory behaviors ranging from sheet-like mass migration in the cephalic regions to chain migration in the trunk. During their journey, neural crest cells rely on a range of signals both from their environment and within the migrating population for navigating through the embryo as a collective. Here we review these interactions and mechanisms, including chemotactic cues of neural crest cells’ migration.

scholarly journals The hypoxia factor Hif-1α controls neural crest chemotaxis and epithelial to mesenchymal transition

2013 ◽  
Vol 201 (5) ◽  
pp. 759-776 ◽  
Author(s):  
Elias H. Barriga ◽  
Patrick H. Maxwell ◽  
Ariel E. Reyes ◽  
Roberto Mayor
Keyword(s):  
Neural Crest ◽  
Cancer Metastasis ◽  
Epithelial To Mesenchymal Transition ◽  
Neural Crest Cells ◽  
Embryonic Cell ◽  
Zebrafish Embryos ◽  
Mesenchymal Transition ◽  
Metastasis Inhibition ◽  
Neural Crest Migration ◽  
Transcription Factor 1

One of the most important mechanisms that promotes metastasis is the stabilization of Hif-1 (hypoxia-inducible transcription factor 1). We decided to test whether Hif-1α also was required for early embryonic development. We focused our attention on the development of the neural crest, a highly migratory embryonic cell population whose behavior has been likened to cancer metastasis. Inhibition of Hif-1α by antisense morpholinos in Xenopus laevis or zebrafish embryos led to complete inhibition of neural crest migration. We show that Hif-1α controls the expression of Twist, which in turn represses E-cadherin during epithelial to mesenchymal transition (EMT) of neural crest cells. Thus, Hif-1α allows cells to initiate migration by promoting the release of cell–cell adhesions. Additionally, Hif-1α controls chemotaxis toward the chemokine SDF-1 by regulating expression of its receptor Cxcr4. Our results point to Hif-1α as a novel and key regulator that integrates EMT and chemotaxis during migration of neural crest cells.

scholarly journals Early Development of The Trunk Neural Crest Cells in the Egyptian Cobra Naja H. Haje

2021 ◽  
Author(s):  
Eraqi R. Khannoon ◽  
Christian Alvarado ◽  
Maria Elena Elena de Bellard
Keyword(s):  
Embryonic Development ◽  
Neural Crest ◽  
Early Development ◽  
Cancer Metastasis ◽  
Epithelial To Mesenchymal Transition ◽  
Early Stage ◽  
Neural Crest Cells ◽  
Migratory Behavior ◽  
Mesenchymal Transition ◽  
Trunk Neural Crest

Abstract Background: Trunk neural crest cells (TNCC) are representing a model for epithelial to mesenchymal transition, this correlates the importance of studying the migration of these cells to cancer metastasis. Reptiles are unique group of animals being very morphologically diverse and their close position to synapsid leading to mammals. Recently, more publications focused on the migratory behavior of trunk NCC during embryonic development of squamates. Only one colubrid snake has been studied so far regarding the NCC migration. Results: Here we follow the migratory behavior of TNCC with HNK1 in the elapid snake Naja h. haje from early stage to 14 days postoviposition. Comparing the colubrid snake with the Egyptian cobra showed that both snakes overall follow the same TNCC migratory pathways of both birds and mammals by following the rostral and avoiding the caudal portions of the somites. Conclusions: First, TNCC intra-somitic migration as observed in turtles supports a contributing role for TNCC to scale precursors. Second, our observation of significant numbers of migrating TNCC in the intersomitic pathway suggest interesting evolutionary differences. Together, our present results of the Egyptian cobra in combination with those on a colubrid and turtle supports intersomitic TNCC as a unique reptile phenomena.

scholarly journals Supracellular contraction at the rear of neural crest cell groups drives collective chemotaxis

Science ◽  
2018 ◽  
Vol 362 (6412) ◽  
pp. 339-343 ◽  
Author(s):  
Adam Shellard ◽  
András Szabó ◽  
Xavier Trepat ◽  
Roberto Mayor
Keyword(s):  
Neural Crest ◽  
Ex Vivo ◽  
Embryonic Stem ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Stem Cell Population ◽  
Cell Group ◽  
Cell Groups ◽  
Cell Chemotaxis

Collective cell chemotaxis, the directed migration of cell groups along gradients of soluble chemical cues, underlies various developmental and pathological processes. We use neural crest cells, a migratory embryonic stem cell population whose behavior has been likened to malignant invasion, to study collective chemotaxis in vivo. StudyingXenopusand zebrafish, we have shown that the neural crest exhibits a tensile actomyosin ring at the edge of the migratory cell group that contracts in a supracellular fashion. This contractility is polarized during collective cell chemotaxis: It is inhibited at the front but persists at the rear of the cell cluster. The differential contractility drives directed collective cell migration ex vivo and in vivo through the intercalation of rear cells. Thus, in neural crest cells, collective chemotaxis works by rear-wheel drive.

scholarly journals LMO4 is an Essential Cofactor in the Snail2-Mediated Epithelial-to-Mesenchymal Transition of Neuroblastoma and Neural Crest Cells

2013 ◽  
Vol 33 (7) ◽  
pp. 2773-2783 ◽  
Author(s):  
T. Ferronha ◽  
M. A. Rabadan ◽  
E. Gil-Guinon ◽  
G. Le Dreau ◽  
C. de Torres ◽  
...  
Keyword(s):  
Neural Crest ◽  
Epithelial To Mesenchymal Transition ◽  
Neural Crest Cells ◽  
Mesenchymal Transition

scholarly journals Cadherin-6B is proteolytically processed during epithelial-to-mesenchymal transitions of the cranial neural crest

2014 ◽  
Vol 25 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Andrew T. Schiffmacher ◽  
Rangarajan Padmanabhan ◽  
Sharon Jhingory ◽  
Lisa A. Taneyhill
Keyword(s):  
Neural Crest ◽  
Epithelial To Mesenchymal Transition ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Spatiotemporal Pattern ◽  
Cranial Neural Crest ◽  
Mesenchymal Transition ◽  
Crest Cell

The epithelial-to-mesenchymal transition (EMT) is a highly coordinated process underlying both development and disease. Premigratory neural crest cells undergo EMT, migrate away from the neural tube, and differentiate into diverse cell types during vertebrate embryogenesis. Adherens junction disassembly within premigratory neural crest cells is one component of EMT and, in chick cranial neural crest cells, involves cadherin-6B (Cad6B) down-regulation. Whereas Cad6B transcription is repressed by Snail2, the rapid loss of Cad6B protein during EMT is suggestive of posttranslational mechanisms that promote Cad6B turnover. For the first time in vivo, we demonstrate Cad6B proteolysis during neural crest cell EMT, which generates a Cad6B N-terminal fragment (NTF) and two C-terminal fragments (CTF1/2). Coexpression of relevant proteases with Cad6B in vitro shows that a disintegrin and metalloproteinases (ADAMs) ADAM10 and ADAM19, together with γ-secretase, cleave Cad6B to produce the NTF and CTFs previously observed in vivo. Of importance, both ADAMs and γ-secretase are expressed in the appropriate spatiotemporal pattern in vivo to proteolytically process Cad6B. Overexpression or depletion of either ADAM within premigratory neural crest cells prematurely reduces or maintains Cad6B, respectively. Collectively these results suggest a dual mechanism for Cad6B proteolysis involving two ADAMs, along with γ-secretase, during cranial neural crest cell EMT.

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