Folate deficiency prevents neural crest fate by disturbing the epigenetic Sox2 repression on the dorsal neural tube

SummaryFibroblast growth factor (FGF) signalling acts as one of modulators that control neural crest cell (NCC) migration, but how this is achieved is still unclear. In this study, we investigated the effects of FGF signalling on NCC migration by blocking this process. Constructs that were capable of inducing Sprouty2 (Spry2) or dominant-negative FGFR1 (Dn-FGFR1) expression were transfected into the cells making up the neural tubes. Our results revealed that blocking FGF signalling at stage HH10 (neurulation stage) could enhance NCC migration at both the cranial and trunk levels in the developing embryos. It was established that FGF-mediated NCC migration was not due to altering the expression of N-cadherin in the neural tube. Instead, we determined that cyclin D1 was overexpressed in the cranial and trunk levels when Sprouty2 was upregulated in the dorsal neural tube. These results imply that the cell cycle was a target of FGF signalling through which it regulates NCC migration at the neurulation stage.

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Bimodal function of chromatin remodeler Hmga1 in neural crest induction and Wnt-dependent emigration

eLife ◽

10.7554/elife.57779 ◽

2020 ◽

Vol 9 ◽

Cited By ~ 1

Author(s):

Shashank Gandhi ◽

Erica J Hutchins ◽

Krystyna Maruszko ◽

Jong H Park ◽

Matthew Thomson ◽

...

Keyword(s):

Neural Crest ◽

Neural Tube ◽

Neural Crest Cells ◽

Neural Plate ◽

Chromatin Remodeler ◽

Lineage Specification ◽

Dorsal Neural Tube ◽

Neural Crest Development ◽

Neural Plate Border ◽

Canonical Wnt

During gastrulation, neural crest cells are specified at the neural plate border, as characterized by Pax7 expression. Using single-cell RNA sequencing coupled with high-resolution in situ hybridization to identify novel transcriptional regulators, we show that chromatin remodeler Hmga1 is highly expressed prior to specification and maintained in migrating chick neural crest cells. Temporally controlled CRISPR-Cas9-mediated knockouts uncovered two distinct functions of Hmga1 in neural crest development. At the neural plate border, Hmga1 regulates Pax7-dependent neural crest lineage specification. At premigratory stages, a second role manifests where Hmga1 loss reduces cranial crest emigration from the dorsal neural tube independent of Pax7. Interestingly, this is rescued by stabilized ß-catenin, thus implicating Hmga1 as a canonical Wnt activator. Together, our results show that Hmga1 functions in a bimodal manner during neural crest development to regulate specification at the neural plate border, and subsequent emigration from the neural tube via canonical Wnt signaling.

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An SEM analysis of neural crest migration in the mouse

Development ◽

10.1242/dev.74.1.97 ◽

1983 ◽

Vol 74 (1) ◽

pp. 97-118

Author(s):

C. A. Erickson ◽

J. A. Weston

Keyword(s):

Neural Crest ◽

Basal Lamina ◽

Neural Tube ◽

Neural Crest Cells ◽

Sem Analysis ◽

Basement Membranes ◽

Dorsal Neural Tube ◽

Trunk Neural Crest ◽

Unique Cell ◽

Neural Crest Migration

The cellular morphology and migratory pathways of the trunk neural crest are described in normal mouse embryos, and in embryos homozygous for Patch in which neural crest derivatives develop abnormally. Trunk neural crest cells initially appear in 8½-day embryos as a unique cell population on the dorsal neural tube surface and are relatively rounded. Once they begin to migrate the cells flatten and orient somewhat tangentially to the neural tube, and advance ventrad between the somites and neural tube. At the onset of migration neural crest cells extend lamellipodia onto the surface of the tube while detaching their trailing processes from the lumenal surface. The basal lamina on the dorsal neural tube is discontinuous when cell migration begins in this region. As development proceeds, the basal lamina gradually becomes continuous from a lateral to dorsal direction and neural crest emigration is progressively confined to the narrowing region of discontinuous basal lamina. Cell separation from the neural tube ceases concomitant with completion of a continuous basement membrane. Preliminary observations of the mutant embryos reveal that abnormal extracellular spaces appear and patterns of crest migration are subsequently altered. We conclude that the extracellular matrix, extracellular spaces and basement membranes may delimit crest migration in the mouse.

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Inhibition of noggin expression in the dorsal neural tube by somitogenesis: a mechanism for coordinating the timing of neural crest emigration

Development ◽

10.1242/dev.127.22.4845 ◽

2000 ◽

Vol 127 (22) ◽

pp. 4845-4854 ◽

Cited By ~ 2

Author(s):

D. Sela-Donenfeld ◽

C. Kalcheim

Keyword(s):

Neural Crest ◽

Neural Tube ◽

Neural Crest Cells ◽

Paraxial Mesoderm ◽

Dorsal Neural Tube ◽

Progressive Loss ◽

Crest Cell ◽

Rostral Part

We have previously shown that axial-dependent delamination of specified neural crest cells is triggered by BMP4 and negatively regulated by noggin. Increasing activity of BMP4 towards the rostral part of the axis is achieved by graded expression of noggin in the dorsal neural tube, the latter being high opposite unsegmented mesoderm, and progressively downregulated facing epithelial and dissociating somites, coinciding in time and axial level with initial delamination of neural crest cells (Sela-Donenfeld, D. and Kalcheim, C. (1999) Development 126, 4749–4762). Here we report that this gradient-like expression of noggin in the neuroepithelium is controlled by the paraxial mesoderm. Deletion of epithelial somites prevented normal downregulation of noggin in the neural tube. Furthermore, partial ablation of either the dorsal half or only the dorsomedial portion of epithelial somites was sufficient to maintain high noggin expression. In contrast, deletion of the segmental plate had no effect. These data suggest that the dorsomedial region of developing somites produces an inhibitor of noggin transcription in the dorsal neural tube. Consistent with this notion, grafting dissociating somites in the place of the unsegmented mesoderm precociously downregulated the expression of noggin and triggered premature emigration of neural crest progenitors from the caudal neural tube. Thus, opposite the unsegmented mesoderm, where noggin expression is high in the neural tube, BMP4 is inactive and neural crest cells fail to delaminate. Upon somitogenesis and further dissociation, the dorsomedial portion of the somite inhibits noggin transcription. Progressive loss of noggin activity releases BMP4 from inhibition, resulting in crest cell emigration. We propose that this inhibitory crosstalk between paraxial mesoderm and neural primordium controls the timing of neural crest delamination to match the development of a suitable mesodermal substrate for subsequent crest migration.

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Effects of Shh and Noggin on neural crest formation demonstrate that BMP is required in the neural tube but not ectoderm

Development ◽

10.1242/dev.125.24.4919 ◽

1998 ◽

Vol 125 (24) ◽

pp. 4919-4930 ◽

Cited By ~ 18

Author(s):

M.A. Selleck ◽

M.I. Garcia-Castro ◽

K.B. Artinger ◽

M. Bronner-Fraser

Keyword(s):

Neural Crest ◽

Sonic Hedgehog ◽

Neural Tube ◽

Neural Crest Cells ◽

Neural Plate ◽

Bmp Signaling ◽

Neural Tube Closure ◽

Dorsal Neural Tube ◽

Neural Ectoderm ◽

Tube Closure

To define the timing of neural crest formation, we challenged the fate of presumptive neural crest cells by grafting notochords, Sonic Hedgehog- (Shh) or Noggin-secreting cells at different stages of neurulation in chick embryos. Notochords or Shh-secreting cells are able to prevent neural crest formation at open neural plate levels, as assayed by DiI-labeling and expression of the transcription factor, Slug, suggesting that neural crest cells are not committed to their fate at this time. In contrast, the BMP signaling antagonist, Noggin, does not repress neural crest formation at the open neural plate stage, but does so if injected into the lumen of the closing neural tube. The period of Noggin sensitivity corresponds to the time when BMPs are expressed in the dorsal neural tube but are down-regulated in the non-neural ectoderm. To confirm the timing of neural crest formation, Shh or Noggin were added to neural folds at defined times in culture. Shh inhibits neural crest production at early stages (0-5 hours in culture), whereas Noggin exerts an effect on neural crest production only later (5-10 hours in culture). Our results suggest three phases of neurulation that relate to neural crest formation: (1) an initial BMP-independent phase that can be prevented by Shh-mediated signals from the notochord; (2) an intermediate BMP-dependent phase around the time of neural tube closure, when BMP-4 is expressed in the dorsal neural tube; and (3) a later pre-migratory phase which is refractory to exogenous Shh and Noggin.

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The role of the neural crest in cardiac development

10.1093/med/9780198757269.003.0019 ◽

2018 ◽

Author(s):

Laura A. Dyer ◽

Margaret L. Kirby

Keyword(s):

Neural Crest ◽

Neural Tube ◽

Heart Development ◽

Cardiac Development ◽

Signalling Pathways ◽

Pharyngeal Arches ◽

Cardiac Neural Crest ◽

Final Destination ◽

Dorsal Neural Tube

The cardiac neural crest (CNC) plays pivotal roles in numerous steps of cardiac development. Every aspect of the CNC cell’s lifespan is highly orchestrated, from its induction in the dorsal neural tube to its migration to its differentiation at its final destination. During migration, CNC cells are affected by their environment and simultaneously modulate the extra-cellular milieu through which they migrate. In the pharyngeal arches, CNC cells repattern the originally symmetrical arch arteries, producing the great arteries. Because the cardiac neural crest is essential for many aspects of heart development, it is unsurprising that human CNC-related syndromes have severe phenotypes. This chapter describes how CNC cells are formed and contribute to their final destinations. Essential signalling pathways are presented in the context of CNC development, and CNC-related syndromes are included to highlight this population’s broad importance during development.

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The regeneration of the cephalic neural crest, a problem revisited: the regenerating cells originate from the contralateral or from the anterior and posterior neural fold

Development ◽

10.1242/dev.122.11.3393 ◽

1996 ◽

Vol 122 (11) ◽

pp. 3393-3407 ◽

Cited By ~ 31

Author(s):

G. Couly ◽

A. Grapin-Botton ◽

P. Coltey ◽

N.M. Le Douarin

Keyword(s):

Neural Crest ◽

Neural Tube ◽

Hox Genes ◽

Experimental Situation ◽

Neural Crest Cells ◽

Fate Map ◽

Somite Stage ◽

Dorsal Neural Tube ◽

Ventral Neural Tube ◽

Branchial Arches

The mesencephalic and rhombencephalic levels of origin of the hypobranchial skeleton (lower jaw and hyoid bone) within the neural fold have been determined at the 5-somite stage with a resolution corresponding to each single rhombomere, by means of the quail-chick chimera technique. Expression of certain Hox genes (Hoxa-2, Hoxa-3 and Hoxb-4) was recorded in the branchial arches of chick and quail embryos at embryonic days 3 (E3) and E4. This was a prerequisite for studying the regeneration capacities of the neural crest, after the dorsal neural tube was resected at the mesencephalic and rhombencephalic level. We found first that excisions at the 5-somite stage extending from the midmesencephalon down to r8 are followed by the regeneration of neural crest cells able to compensate for the deficiencies so produced. This confirmed the results of previous authors who made similar excisions at comparable (or older) developmental stages. When a bilateral excision was followed by the unilateral homotopic graft of the dorsal neural tube from a quail embryo, thus mimicking the situation created by a unilateral excision, we found that the migration of the grafted unilateral neural crest (quail-labelled) is bilateral and compensates massively for the missing crest derivatives. The capacity of the intermediate and ventral neural tube to yield neural crest cells was tested by removing the chick rhombencephalic neural tube and replacing it either uni- or bilaterally with a ventral tube coming from a stage-matched quail. No neural crest cells exited from the ventral neural tube but no deficiency in neural crest derivatives was recorded. Crest cells were found to regenerate from the ends of the operated region. This was demonstrated by grafting fragments of quail neural fold at the extremities of the excised territory. Quail neural crest cells were seen migrating longitudinally from both the rostral and caudal ends of the operated region and filling the branchial arches located inbetween. Comparison of the behaviour of neural crest cells in this experimental situation with that showed by their normal fate map revealed that crest cells increase their proliferation rate and change their migratory behaviour without modifying their Hox code.

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Regulation of the onset of neural crest migration by coordinated activity of BMP4 and Noggin in the dorsal neural tube

Development ◽

10.1242/dev.126.21.4749 ◽

1999 ◽

Vol 126 (21) ◽

pp. 4749-4762 ◽

Cited By ~ 22

Author(s):

D. Sela-Donenfeld ◽

C. Kalcheim

Keyword(s):

Neural Crest ◽

Neural Tube ◽

Specific Inhibitor ◽

Neural Crest Cells ◽

Concomitant Treatment ◽

Neural Tubes ◽

Dorsal Neural Tube ◽

Dependent Inhibition ◽

Neural Crest Migration

For neural crest cells to engage in migration, it is necessary that epithelial premigratory crest cells convert into mesenchyme. The mechanisms that trigger cell delamination from the dorsal neural tube remain poorly understood. We find that, in 15- to 40-somite-stage avian embryos, BMP4 mRNA is homogeneously distributed along the longitudinal extent of the dorsal neural tube, whereas its specific inhibitor noggin exists in a gradient of expression that decreases caudorostrally. This rostralward reduction in signal intensity coincides with the onset of emigration of neural crest cells. Hence, we hypothesized that an interplay between Noggin and BMP4 in the dorsal tube generates graded concentrations of the latter that in turn triggers the delamination of neural crest progenitors. Consistent with this suggestion, disruption of the gradient by grafting Noggin-producing cells dorsal to the neural tube at levels opposite the segmental plate or newly formed somites, inhibited emigration of HNK-1-positive crest cells, which instead accumulated within the dorsal tube. Similar results were obtained with explanted neural tubes from the same somitic levels exposed to Noggin. Exposure to Follistatin, however, had no effect. The Noggin-dependent inhibition was overcome by concomitant treatment with BMP4, which when added alone, also accelerated cell emigration compared to untreated controls. Furthermore, the observed inhibition of neural crest emigration in vivo was preceded by a partial or total reduction in the expression of cadherin-6B and rhoB but not in the expression of slug mRNA or protein. Altogether, these results suggest that a coordinated activity of Noggin and BMP4 in the dorsal neural tube triggers delamination of specified, slug-expressing neural crest cells. Thus, BMPs play multiple and discernible roles at sequential stages of neural crest ontogeny, from specification through delamination and later differentiation of specific neural crest derivatives.

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