scholarly journals Craniofacial transitions: the role of EMT and MET during head development

Development ◽  
2021 ◽  
Vol 148 (4) ◽  
pp. dev196030
Author(s):  
Natalie J. Milmoe ◽  
Abigail S. Tucker

ABSTRACTWithin the developing head, tissues undergo cell-fate transitions to shape the forming structures. This starts with the neural crest, which undergoes epithelial-to-mesenchymal transition (EMT) to form, amongst other tissues, many of the skeletal tissues of the head. In the eye and ear, these neural crest cells then transform back into an epithelium, via mesenchymal-to-epithelial transition (MET), highlighting the flexibility of this population. Elsewhere in the head, the epithelium loses its integrity and transforms into mesenchyme. Here, we review these craniofacial transitions, looking at why they happen, the factors that trigger them, and the cell and molecular changes they involve. We also discuss the consequences of aberrant EMT and MET in the head.

2018 ◽  
Vol 52 (1) ◽  
pp. 43-63 ◽  
Author(s):  
András Szabó ◽  
Roberto Mayor

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.


2013 ◽  
Vol 201 (5) ◽  
pp. 759-776 ◽  
Author(s):  
Elias H. Barriga ◽  
Patrick H. Maxwell ◽  
Ariel E. Reyes ◽  
Roberto Mayor

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.


2016 ◽  
Vol 13 (118) ◽  
pp. 20151106 ◽  
Author(s):  
Marcelo Boareto ◽  
Mohit Kumar Jolly ◽  
Aaron Goldman ◽  
Mika Pietilä ◽  
Sendurai A. Mani ◽  
...  

Metastasis can involve repeated cycles of epithelial-to-mesenchymal transition (EMT) and its reverse mesenchymal-to-epithelial transition. Cells can also undergo partial transitions to attain a hybrid epithelial/mesenchymal (E/M) phenotype that allows the migration of adhering cells to form a cluster of circulating tumour cells. These clusters can be apoptosis-resistant and possess an increased metastatic propensity as compared to the cells that undergo a complete EMT (mesenchymal cells). Hence, identifying the key players that can regulate the formation and maintenance of such clusters may inform anti-metastasis strategies. Here, we devise a mechanism-based theoretical model that links cell–cell communication via Notch-Delta-Jagged signalling with the regulation of EMT. We demonstrate that while both Notch-Delta and Notch-Jagged signalling can induce EMT in a population of cells, only Jagged-dominated Notch signalling, but not Delta-dominated signalling, can lead to the formation of clusters containing hybrid E/M cells. Our results offer possible mechanistic insights into the role of Jagged in tumour progression, and offer a framework to investigate the effects of other microenvironmental signals during metastasis.


2021 ◽  
Author(s):  
Heyang Xu ◽  
Qiusheng Lan ◽  
Yongliang Huang ◽  
Yang Zhang ◽  
Yujie Zeng ◽  
...  

Abstract Background: Liver metastasis is the most common cause of death in patients with colorectal cancer (CRC). Phosphatase of regenerating liver-3 induces CRC metastasis by epithelial-to-mesenchymal transition, which promotes CRC cell liver metastasis. Mesenchymal-to-epithelial transition (MET), the opposite of epithelial-to-mesenchymal transition, has been proposed as a mechanism for the establishment of metastatic neoplasms. However, the molecular mechanism of MET remains unclear. Methods: Using Immunohistochemistry, western blotting,invasion assays, real-time quantitative PCR, chromatin immunoprecipitation, luciferase reporter assays, human miRNA arrays, and xenograft mouse model, we determined the role of hepatocyte exosome-derived miR-203a-3p in CRC MET.Results: In our study, we found that miR-203a-3p derived from hepatocyte exosomes increased colorectal cancer cells E-cadherin expression, inhibited Src expression, and reduced activity. In this way miR-203a-3p induced the decreased invasion rate of CRC cells.Coclusion: MiR-203a-3p derived from hepatocyte exosomes plays an important role of CRC cells to colonize in liver.


2021 ◽  
Author(s):  
Eraqi R. Khannoon ◽  
Christian Alvarado ◽  
Maria Elena Elena de Bellard

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.


2021 ◽  
Author(s):  
Riley Galton ◽  
Katalin Fejes-Toth ◽  
Marianne E. Bronner

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.


2013 ◽  
Vol 33 (7) ◽  
pp. 2773-2783 ◽  
Author(s):  
T. Ferronha ◽  
M. A. Rabadan ◽  
E. Gil-Guinon ◽  
G. Le Dreau ◽  
C. de Torres ◽  
...  

2014 ◽  
Vol 25 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Andrew T. Schiffmacher ◽  
Rangarajan Padmanabhan ◽  
Sharon Jhingory ◽  
Lisa A. Taneyhill

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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