Integrin-Mediated Focal Anchorage Drives Epithelial Zippering during Mouse Neural Tube Closure.
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ABSTRACT:
SUBMITTER: Mole MA
PROVIDER: S-EPMC7008250 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Zippering is a phenomenon of tissue morphogenesis whereby fusion between opposing epithelia progresses unidirectionally over significant distances, similar to the travel of a zip fastener, to ultimately ensure closure of an opening. A comparable process can be observed during Drosophila dorsal closure and mammalian wound healing, while zippering is employed by numerous organs such as the optic fissure, palatal shelves, tracheoesophageal foregut, and presumptive genitalia to mediate tissue sealing during normal embryonic development. Particularly striking is zippering propagation during neural tube morphogenesis, where the fusion point travels extensively along the embryonic axis to ensure closure of the neural tube. Advances in time-lapse microscopy and culture conditions have opened the opportunity for successful imaging of whole-mouse embryo development over time, providing insights into the precise cellular behavior underlying zippering propagation. Studies in mouse and the ascidian Ciona have revealed the fine-tuned cell shape changes and junction remodeling which occur at the site of zippering during neural tube morphogenesis. Here, we describe a step-by-step method for imaging at single-cell resolution the process of zippering and tissue remodeling which occurs during closure of the spinal neural tube in mouse. We also provide instructions and suggestions for quantitative morphometric analysis of cell behavior during zippering progression. This procedure can be further combined with genetic mutant models (e.g., knockouts), offering the possibility of studying the dynamics of tissue fusion and zippering propagation, which underlie a wide range of open neural tube defects.
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Project description:This SuperSeries is composed of the SubSeries listed below.
2021-02-25 | GSE167456 | GEO
Project description:Neural tube (NT) formation in the spinal region of the mammalian embryo involves a wave of "zippering" that passes down the elongating spinal axis, uniting the neural fold tips in the dorsal midline. Failure of this closure process leads to open spina bifida, a common cause of severe neurologic disability in humans. Here, we combined a tissue-level strain-mapping workflow with laser ablation of live-imaged mouse embryos to investigate the biomechanics of mammalian spinal closure. Ablation of the zippering point at the embryonic dorsal midline causes far-reaching, rapid separation of the elevating neural folds. Strain analysis revealed tissue expansion around the zippering point after ablation, but predominant tissue constriction in the caudal and ventral neural plate zone. This zone is biomechanically coupled to the zippering point by a supracellular F-actin network, which includes an actin cable running along the neural fold tips. Pharmacologic inhibition of F-actin or laser ablation of the cable causes neural fold separation. At the most advanced somite stages, when completion of spinal closure is imminent, the cable forms a continuous ring around the neuropore, and simultaneously, a new caudal-to-rostral zippering point arises. Laser ablation of this new closure initiation point causes neural fold separation, demonstrating its biomechanical activity. Failure of spinal closure in pre-spina bifida Zic2Ku mutant embryos is associated with altered tissue biomechanics, as indicated by greater neuropore widening after ablation. Thus, this study identifies biomechanical coupling of the entire region of active spinal neurulation in the mouse embryo as a prerequisite for successful NT closure.
| S-EPMC5495245 | biostudies-literature
Project description:Bending of the neural plate at paired dorsolateral hinge points (DLHPs) is required for neural tube closure in the spinal region of the mouse embryo. As a step towards understanding the morphogenetic mechanism of DLHP development, we examined variations in neural plate cellular architecture and proliferation during closure. Neuroepithelial cells within the median hinge point (MHP) contain nuclei that are mainly basally located and undergo relatively slow proliferation, with a 7 h cell cycle length. In contrast, cells in the dorsolateral neuroepithelium, including the DLHP, exhibit nuclei distributed throughout the apico-basal axis and undergo rapid proliferation, with a 4 h cell cycle length. As the neural folds elevate, cell numbers increase to a greater extent in the dorsolateral neural plate that contacts the surface ectoderm, compared with the more ventromedial neural plate where cells contact paraxial mesoderm and notochord. This marked increase in dorsolateral cell number cannot be accounted for solely on the basis of enhanced cell proliferation in this region. We hypothesised that neuroepithelial cells may translocate in a ventral-to-dorsal direction as DLHP formation occurs, and this was confirmed by vital cell labelling in cultured embryos. The translocation of cells into the neural fold, together with its more rapid cell proliferation, leads to an increase in cell density dorsolaterally compared with the more ventromedial neural plate. These findings suggest a model in which DLHP formation may proceed through 'buckling' of the neuroepithelium at a dorso-ventral boundary marked by a change in cell-packing density.
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Project description:BMPs have been shown to play a role in neural tube development particularly as dorsalizing factors. To explore the possibility that BMP2 could play a role in the developing neural tube (NT) beyond the lethality of Bmp2 null embryos, we created Bmp2 chimeras from Bmp2 null ES cells and WT blastocysts. Analysis of Bmp2 chimeras reveals NT defects at day 9.5 (E9.5). We found that exclusion of Bmp2 null ES cells from the dorsal NT did not always prevent defects. For further comparison, we used a Bmp2 mutant line in a mixed background. Phenotypes observed were similar to chimeras including open NT defects, postneurulation defects, and abnormal neural ectoderm in heterozygous and homozygous null embryos demonstrating a pattern of dose-dependent signaling. Our data exposes BMP2 as a unique player in the developing NT for dorsal patterning and identity, and normal cephalic neural tube closure in a dose-dependent manner.
| S-EPMC3086576 | biostudies-other
Project description:This data series was used for two separate studies. The initial study was aimed to idenify expression changes brought about by the Cecr2Gt45Bic mutation during neural closure. The study included two different strains, BALB/cCrl in which Cecr2GT45Bic shows a neural tube defect phenotype and FVB/N in which Cecr2Gt45Bic does not manifest neural closure defects. The second was to idenify strain specific expression differences present during neural closure of the mouse embryo between BALB/cCrl and FVB/N in order to identify candidate modifiers of the Cecr2Gt45Bic neural tube defect. Relevant abstracts are included below. The initial study ; BACKGROUND: Over 200 mouse genes are associated with neural tube defects (NTDs), including Cecr2, the bromodomain-containing subunit of the CERF chromatin remodeling complex. METHODS: Gene-trap mutation Cecr2Gt45Bic results in 74% exencephaly (equivalent of human anencephaly) on the BALB/c strain. Gene expression altered during cranial neural tube closure by the Cecr2 mutation was identified through microarray analysis of 11M-bM-^@M-^S14 somites stage Cecr2Gt45Bicembryos. RESULTS: Analysis of Affymetrix Mouse 430 2.0 chips detected 60 transcripts up-regulated and 54 transcripts down-regulated in the Cecr2Gt45Bic embryos (fold > 1.5, p < 0.05). The Cecr2 transcript was reduced only M-bM-^HM-<7- to 14-fold from normal levels, suggesting the Cecr2Gt45Bic is a hypomorphic mutation. We therefore generated a novel Cecr2 null allele (Cecr2tm1.1Hemc). Resulting mutants displayed a stronger penetrance of exencephaly than Cecr2Gt45Bic in both BALB/c and FVB/N strains, in addition to midline facial clefts and forebrain encephalocele in the FVB/N strain. The Cecr2 transcript is reduced 260-fold in the Cecr2tm1.1Hemc line. Subsequent qRT-PCR using Cecr2tm1.1Hemc mutant heads confirmed downregulation of transcription factors Alx1/Cart1,Dlx5, Eya1, and Six1. CONCLUSIONS: As both Alx1/Cart1 and Dlx5 mouse mutations result in exencephaly, we hypothesize that changes in expression of these mesenchymal/ectodermal transcription factors may contribute to NTDs associated with Cecr2. Birth Defects Research (Part A), 2010. 010 Wiley-Liss, Inc. The second study: ABSTRACT:Although neural tube defects (NTDs) are common in humans, little is known about their multifactorial genetic causes. While most mouse models involve NTDs caused by a single mutated gene, we have previously described a multigenic system involving susceptibility to NTDs. In mice with a mutation in Cecr2, the cranial NTD exencephaly shows strain specific differences in penetrance, with 74% penetrance in BALB/cCrl and 0% penetrance in FVB/N. Whole genome linkage analysis showed that a region of chromosome 19 was partially responsible for this difference in penetrance. We now reveal by genetic analysis of three subinterval congenic lines that the chromosome 19 region contains more than one modifier gene. Analysis of embryos showed that although a Cecr2 mutation causes wider neural tubes in both strains, FVB/N embryos overcome this abnormality and close. A microarray analysis comparing neurulating female embryos from both strains identified differentially expressed genes within the chromosome 19 region, including Arhgap19, which is expressed at a lower level in BALB/cCrl due to a stop codon specific to that substrain. Modifier genes in this region are of particular interest because it is syntenic to human chromosome 10q25, the site of a human susceptibility locus. (MANUSCRIPT PENDING SUBMISSION) Thieler STAGE 13-14 (11-14 somite) female embryos where disected away from extraembryonic membranes for RNA extraction and hybridization on Affymetrix microarrays. A single embryo was processed per array, with four biological replicates per genotype BALB/cCrl, Cecr2GT45Bic BALB/cCrl, FVB/N, and Cecr2Gt45Bic FVB/N.
2012-02-27 | E-GEOD-30957 | biostudies-arrayexpress
Project description:Susceptibility to neural tube defects (NTDs), such as anencephaly and spina bifida is influenced by genetic and environmental factors including maternal nutrition. Maternal periconceptional supplementation with folic acid significantly reduces the risk of an NTD-affected pregnancy, but does not prevent all NTDs, and "folic acid non-responsive" NTDs continue to occur. Similarly, among mouse models of NTDs, some are responsive to folic acid but others are not. Among nutritional factors, inositol deficiency causes cranial NTDs in mice while supplemental inositol prevents spinal and cranial NTDs in the curly tail (Grhl3 hypomorph) mouse, rodent models of hyperglycemia or induced diabetes, and in a folate-deficiency induced NTD model. NTDs also occur in mice lacking expression of certain inositol kinases. Inositol-containing phospholipids (phosphoinositides) and soluble inositol phosphates mediate a range of functions, including intracellular signaling, interaction with cytoskeletal proteins, and regulation of membrane identity in trafficking and cell division. Myo-inositol has been trialed in humans for a range of conditions and appears safe for use in human pregnancy. In pilot studies in Italy and the United Kingdom, women took inositol together with folic acid preconceptionally, after one or more previous NTD-affected pregnancies. In nonrandomized cohorts and a randomized double-blind study in the United Kingdom, no recurrent NTDs were observed among 52 pregnancies reported to date. Larger-scale fully powered trials are needed to determine whether supplementation with inositol and folic acid would more effectively prevent NTDs than folic acid alone. Birth Defects Research 109:68-80, 2017. © 2016 The Authors Birth Defects Research Published by Wiley Periodicals, Inc.
| S-EPMC5353661 | biostudies-literature
Project description:This data series was used for two separate studies. The initial study was aimed to idenify expression changes brought about by the Cecr2Gt45Bic mutation during neural closure. The study included two different strains, BALB/cCrl in which Cecr2GT45Bic shows a neural tube defect phenotype and FVB/N in which Cecr2Gt45Bic does not manifest neural closure defects. The second was to idenify strain specific expression differences present during neural closure of the mouse embryo between BALB/cCrl and FVB/N in order to identify candidate modifiers of the Cecr2Gt45Bic neural tube defect. Relevant abstracts are included below. The initial study ; BACKGROUND: Over 200 mouse genes are associated with neural tube defects (NTDs), including Cecr2, the bromodomain-containing subunit of the CERF chromatin remodeling complex. METHODS: Gene-trap mutation Cecr2Gt45Bic results in 74% exencephaly (equivalent of human anencephaly) on the BALB/c strain. Gene expression altered during cranial neural tube closure by the Cecr2 mutation was identified through microarray analysis of 11–14 somites stage Cecr2Gt45Bicembryos. RESULTS: Analysis of Affymetrix Mouse 430 2.0 chips detected 60 transcripts up-regulated and 54 transcripts down-regulated in the Cecr2Gt45Bic embryos (fold > 1.5, p < 0.05). The Cecr2 transcript was reduced only ∼7- to 14-fold from normal levels, suggesting the Cecr2Gt45Bic is a hypomorphic mutation. We therefore generated a novel Cecr2 null allele (Cecr2tm1.1Hemc). Resulting mutants displayed a stronger penetrance of exencephaly than Cecr2Gt45Bic in both BALB/c and FVB/N strains, in addition to midline facial clefts and forebrain encephalocele in the FVB/N strain. The Cecr2 transcript is reduced 260-fold in the Cecr2tm1.1Hemc line. Subsequent qRT-PCR using Cecr2tm1.1Hemc mutant heads confirmed downregulation of transcription factors Alx1/Cart1,Dlx5, Eya1, and Six1. CONCLUSIONS: As both Alx1/Cart1 and Dlx5 mouse mutations result in exencephaly, we hypothesize that changes in expression of these mesenchymal/ectodermal transcription factors may contribute to NTDs associated with Cecr2. Birth Defects Research (Part A), 2010. 010 Wiley-Liss, Inc. The second study: ABSTRACT:Although neural tube defects (NTDs) are common in humans, little is known about their multifactorial genetic causes. While most mouse models involve NTDs caused by a single mutated gene, we have previously described a multigenic system involving susceptibility to NTDs. In mice with a mutation in Cecr2, the cranial NTD exencephaly shows strain specific differences in penetrance, with 74% penetrance in BALB/cCrl and 0% penetrance in FVB/N. Whole genome linkage analysis showed that a region of chromosome 19 was partially responsible for this difference in penetrance. We now reveal by genetic analysis of three subinterval congenic lines that the chromosome 19 region contains more than one modifier gene. Analysis of embryos showed that although a Cecr2 mutation causes wider neural tubes in both strains, FVB/N embryos overcome this abnormality and close. A microarray analysis comparing neurulating female embryos from both strains identified differentially expressed genes within the chromosome 19 region, including Arhgap19, which is expressed at a lower level in BALB/cCrl due to a stop codon specific to that substrain. Modifier genes in this region are of particular interest because it is syntenic to human chromosome 10q25, the site of a human susceptibility locus. (MANUSCRIPT PENDING SUBMISSION)
2012-02-27 | GSE30957 | GEO
Project description:We report an unexpected role for protease signaling in neural tube closure and the formation of the central nervous system. Mouse embryos lacking protease-activated receptors 1 and 2 showed defective hindbrain and posterior neuropore closure and developed exencephaly and spina bifida, important human congenital anomalies. Par1 and Par2 were expressed in surface ectoderm, and Par2 was expressed selectively along the line of closure. Ablation of G(i/z) and Rac1 function in these Par2-expressing cells disrupted neural tube closure, further implicating G protein-coupled receptors and identifying a likely effector pathway. Cluster analysis of protease and Par2 expression patterns revealed a group of membrane-tethered proteases often coexpressed with Par2. Among these, matriptase activated Par2 with picomolar potency, and hepsin and prostasin activated matriptase. Together, our results suggest a role for protease-activated receptor signaling in neural tube closure and identify a local protease network that may trigger Par2 signaling and monitor and regulate epithelial integrity in this context.
| S-EPMC2822780 | biostudies-literature