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 | 2020 Feb
REPOSITORIES: biostudies-literature
Publications
Integrin-Mediated Focal Anchorage Drives Epithelial Zippering during Mouse Neural Tube Closure.
Molè Matteo A MA Galea Gabriel L GL Rolo Ana A Weberling Antonia A Nychyk Oleksandr O De Castro Sandra C SC Savery Dawn D Fässler Reinhard R Ybot-González Patricia P Greene Nicholas D E NDE Copp Andrew J AJ
Developmental cell 20200201 3
Epithelial fusion is a key process of morphogenesis by which tissue connectivity is established between adjacent epithelial sheets. A striking and poorly understood feature of this process is "zippering," whereby a fusion point moves directionally along an organ rudiment. Here, we uncover the molecular mechanism underlying zippering during mouse spinal neural tube closure. Fusion is initiated via local activation of integrin β1 and focal anchorage of surface ectoderm cells to a shared point of f ...[more]
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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.
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| 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