Prevention of spinal neural tube defects in the mouse embryo by growth retardation during neurulation

Development ◽  
1988 ◽  
Vol 104 (2) ◽  
pp. 297-303 ◽  
Author(s):  
A.J. Copp ◽  
J.A. Crolla ◽  
F.A. Brook

Homozygous mutant curly tail mouse embryos developing spinal neural tube defects (NTD) exhibit a cell-type-specific abnormality of cell proliferation that affects the gut endoderm and notochord but not the neuroepithelium. We suggested that spinal NTD in these embryos may result from the imbalance of cell proliferation rates between affected and unaffected cell types. In order to test this hypothesis, curly tail embryos were subjected to influences that retard growth in vivo and in vitro. The expectation was that growth of unaffected rapidly growing cell types would be reduced to a greater extent than affected slowly growing cell types, thus counteracting the genetically determined imbalance of cell proliferation rates and leading to normalization of spinal neurulation. Food deprivation of pregnant females for 48 h prior to the stage of posterior neuropore closure reduced the overall incidence of spinal NTD and almost completely prevented open spina bifida, the most severe form of spinal NTD in curly tail mice. Analysis of embryos earlier in gestation showed that growth retardation acts by reducing the incidence of delayed neuropore closure. Culture of embryos at 40.5 degrees C for 15–23 h from day 10 of gestation, like food deprivation in vivo, also produced growth retardation and led to normalization of posterior neuropore closure. Labelling of embryos in vitro with [3H]thymidine for 1 h at the end of the culture period showed that the labelling index is reduced to a greater extent in the neuroepithelium than in other cell types in growth-retarded embryos compared with controls cultured at 38 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Development ◽  
1982 ◽  
Vol 69 (1) ◽  
pp. 151-167
Author(s):  
A. J. Copp ◽  
M. J. Seller ◽  
P. E. Polani

A dye-injection technique has been used to determine the developmental stage at which posterior neuropore (PNP) closure occurs in normal and mutant curly tail mouse embryos. In vivo, the majority of non-mutant embryos undergo PNP closure between 30 and 34 somites whereas approximately 50% of all mutant embryos show delayed closure, and around 20% maintain an open PNP even at advanced stages of development. A similar result has been found for embryos developing in vitro from the headfold stage. Later in development, 50–60% of mutant embryos in vivo develop tail flexion defects, and 15–20% lumbosacral myeloschisis. This supports the view that delayed PNP closure is the main developmental lesion leading to the appearance of caudal neural tube defects in curly tail mice. The neural tube is closed in the region of tail flexion defects, but it is locally overexpanded and abnormal in position. The significance of these observations is discussed in relation to possible mechanisms of development of lumbosacral and caudal neural tube defects. This paper constitutes the first demonstration of the development of a genetically induced malformation in vitro.


Development ◽  
1988 ◽  
Vol 104 (2) ◽  
pp. 285-295 ◽  
Author(s):  
A.J. Copp ◽  
F.A. Brook ◽  
H.J. Roberts

The mouse mutant curly tail (ct) provides a model system for studies of neurulation mechanisms. 60% of ct/ct embryos develop spinal neural tube defects (NTD) as a result of delayed neurulation at the posterior neuropore whereas the remaining 40% of embryos develop normally. In order to investigate the role of cell proliferation during mouse neurulation, cell cycle parameters were studied in curly tail embryos developing spinal NTD and in their normally developing litter-mates. Measurements were made of mitotic index, median length of S-phase and percent reduction of labelling index during a [3H]thymidine pulse-chase experiment. These independent measures of cell proliferation rate indicate a reduced rate of proliferation of gut endoderm and notochord cells in the neuropore region of embryos developing spinal NTD compared with normally developing controls. The incidence of cell death and the relative frequency of mitotic spindle orientations does not differ consistently between normal and abnormal embryos. These results suggest a mechanism of spinal NTD pathogenesis in curly tail embryos based on failure of normal cell proliferation in gut endoderm and notochord.


Development ◽  
1991 ◽  
Vol 113 (Supplement_2) ◽  
pp. 105-122 ◽  
Author(s):  
Marysia Placzek ◽  
Toshiya Yamada ◽  
Marc Tessier-Lavigne ◽  
Thomas Jessell ◽  
Jane Dodd

Distinct classes of neural cells differentiate at specific locations within the embryonic vertebrate nervous system. To define the cellular mechanisms that control the identity and pattern of neural cells we have used a combination of functional assays and antigenic markers to examine the differentiation of cells in the developing spinal cord and hindbrain in vivo and in vitro. Our results suggest that a critical step in the dorsoventral patterning of the embryonic CNS is the differentiation of a specialized group of midline neural cells, termed the floor plate, in response to local inductive signals from the underlying notochord. The floor plate and notochord appear to control the pattern of cell types that appear along the dorsoventral axis of the neural tube. The fate of neuroepithelial cells in the ventral neural tube may be defined by cell position with respect to the ventral midline and controlled by polarizing signals that originate from the floor plate and notochord.


Development ◽  
1995 ◽  
Vol 121 (3) ◽  
pp. 681-691
Author(s):  
W.H. Chen ◽  
G.M. Morriss-Kay ◽  
A.J. Copp

A role for all-trans-retinoic acid in spinal neurulation is suggested by: (1) the reciprocal domains of expression of the retinoic acid receptors RAR-beta and RAR-gamma in the region of the closed neural tube and open posterior neuropore, respectively, and (2) the preventive effect of maternally administered retinoic acid (5 mg/kg) on spinal neural tube defects in curly tail (ct/ct) mice. Using in situ hybridisation and computerised image analysis we show here that in ct/ct embryos, RAR-beta transcripts are deficient in the hindgut endoderm, a tissue whose proliferation rate is abnormal in the ct mutant, and RAR-gamma transcripts are deficient in the tail bud and posterior neuropore region. The degree of deficiency of RAR-gamma transcripts is correlated with the severity of delay of posterior neuropore closure. As early as 2 hours following RA treatment at 10 days 8 hours post coitum, i.e. well before any morphogenetic effects are detectable, RAR-beta expression is specifically upregulated in the hindgut endoderm, and the abnormal expression pattern of RAR-gamma is also altered. These results suggest that the spinal neural tube defects which characterise the curly tail phenotype may be due to interaction between the ct gene product and one or more aspects of the retinoic acid signalling pathway.


BMC Cancer ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ethan P. Metz ◽  
Erin L. Wuebben ◽  
Phillip J. Wilder ◽  
Jesse L. Cox ◽  
Kaustubh Datta ◽  
...  

Abstract Background Quiescent tumor cells pose a major clinical challenge due to their ability to resist conventional chemotherapies and to drive tumor recurrence. Understanding the molecular mechanisms that promote quiescence of tumor cells could help identify therapies to eliminate these cells. Significantly, recent studies have determined that the function of SOX2 in cancer cells is highly dose dependent. Specifically, SOX2 levels in tumor cells are optimized to promote tumor growth: knocking down or elevating SOX2 inhibits proliferation. Furthermore, recent studies have shown that quiescent tumor cells express higher levels of SOX2 compared to adjacent proliferating cells. Currently, the mechanisms through which elevated levels of SOX2 restrict tumor cell proliferation have not been characterized. Methods To understand how elevated levels of SOX2 restrict the proliferation of tumor cells, we engineered diverse types of tumor cells for inducible overexpression of SOX2. Using these cells, we examined the effects of elevating SOX2 on their proliferation, both in vitro and in vivo. In addition, we examined how elevating SOX2 influences their expression of cyclins, cyclin-dependent kinases (CDKs), and p27Kip1. Results Elevating SOX2 in diverse tumor cell types led to growth inhibition in vitro. Significantly, elevating SOX2 in vivo in pancreatic ductal adenocarcinoma, medulloblastoma, and prostate cancer cells induced a reversible state of tumor growth arrest. In all three tumor types, elevation of SOX2 in vivo quickly halted tumor growth. Remarkably, tumor growth resumed rapidly when SOX2 returned to endogenous levels. We also determined that elevation of SOX2 in six tumor cell lines decreased the levels of cyclins and CDKs that control each phase of the cell cycle, while upregulating p27Kip1. Conclusions Our findings indicate that elevating SOX2 above endogenous levels in a diverse set of tumor cell types leads to growth inhibition both in vitro and in vivo. Moreover, our findings indicate that SOX2 can function as a master regulator by controlling the expression of a broad spectrum of cell cycle machinery. Importantly, our SOX2-inducible tumor studies provide a novel model system for investigating the molecular mechanisms by which elevated levels of SOX2 restrict cell proliferation and tumor growth.


2009 ◽  
Vol 108 (1) ◽  
pp. 132-148 ◽  
Author(s):  
Måns Jergil ◽  
Kim Kultima ◽  
Anne-Lee Gustafson ◽  
Lennart Dencker ◽  
Michael Stigson

2016 ◽  
Vol 130 (24) ◽  
pp. 2329-2340 ◽  
Author(s):  
Xiaojin Qiao ◽  
Yahui Liu ◽  
Peiqiang Li ◽  
Zhongzhong Chen ◽  
Huili Li ◽  
...  

The planar cell polarity (PCP) pathway is critical for proper embryonic development of the neural tube and heart. Mutations in these genes have previously been implicated in the pathogenesis of neural tube defects (NTDs), but not in congenital heart defects (CHDs) in humans. We systematically identified the mutation patterns of CELSR1–3, one family of the core PCP genes, in human cohorts composed of 352 individuals with NTDs, 412 with CHDs and matched controls. A total of 72 disease-specific, rare, novel, coding mutations were identified, of which 37 were identified in patients with CHDs and 36 in patients with NTDs. Most of these mutations differed between the two cohorts, because only one novel missense mutation in CELSR1 (c.2609G>A p.P870L) was identified in both NTD and CHD patients. Both in vivo and in vitro assays revealed that CELSR1 P870L is a gain-of-function mutation. It up-regulates not only the PCP pathway, but also canonical WNT signalling in cells, and also induces both NTDs and CHDs in zebrafish embryos. As almost equal numbers of mutations were identified in each cohort, our results provided the first evidence that mutations in CELSR genes are as likely to be associated with CHDs as with NTDs, although the specific mutations differ between the two cohorts. Such differences in mutation panels suggested that CELSRs [cadherin, EGF (epidermal growth factor), LAG (laminin A G-type repeat), seven-pass receptors)] might be regulated differently during the development of these two organ systems.


2018 ◽  
Vol 27 (1) ◽  
pp. 31-44 ◽  
Author(s):  
Marta Magatti ◽  
Elsa Vertua ◽  
Anna Cargnoni ◽  
Antonietta Silini ◽  
Ornella Parolini

Among the many cell types useful in developing therapeutic treatments, human amniotic cells from placenta have been proposed as valid candidates. Both human amniotic epithelial and mesenchymal stromal cells, and the conditioned medium generated from their culture, exert multiple immunosuppressive activities. Indeed, they inhibit T and B cell proliferation, suppress inflammatory properties of monocytes, macrophages, dendritic cells, neutrophils, and natural killer cells, while promoting induction of cells with regulatory functions such as regulatory T cells and anti-inflammatory M2 macrophages. These properties have laid the foundation for their use for the treatment of inflammatory-based diseases, and encouraging results have been obtained in different preclinical disease models where exacerbated inflammation is present. Moreover, an immune-privileged status of amniotic cells has been often highlighted. However, even if long-term engraftment of amniotic cells has been reported into immunocompetent animals, only few cells survive after infusion. Furthermore, amniotic cells have been shown to be able to induce immune responses in vivo and, under specific culture conditions, they can stimulate T cell proliferation in vitro. Although immunosuppressive properties are a widely recognized characteristic of amniotic cells, immunogenic and stimulatory activities appear to be less reported, sporadic events. In order to improve therapeutic outcome, the mechanisms responsible for the suppressive versus stimulatory activity need to be carefully addressed. In this review, both the immunosuppressive and immunostimulatory activity of amniotic cells will be discussed.


Development ◽  
1985 ◽  
Vol 88 (1) ◽  
pp. 39-54
Author(s):  
Andrew J. Copp

The relationship between timing of closure of the posterior neuropore (PNP) and development of spinal neural tube defects (NTD) has been studied in individual mutant curly tail mouse embryos maintained in culture. Moderate delay in PNP closure results in development of tail flexion defects whereas extreme delay of PNP closure is associated with development of open NTD. Experimental enlargement of the PNP at the stage of 25 to 29 somites leads to delayed PNP closure and development of tail flexion defects in 36 % and 38 % respectively of non-mutant A/Strong embryos. In curly tail embryos, the effect of experimental enlargement of the PNP summates with the genetic predisposition to produce an increased incidence of spinal NTD among which open defects are proportionately more common. These results indicate that a causal relationship exists between delay in PNP closure and development of spinal NTD in mouse embryos. The method described for distinguishing between prospective normal and abnormal curly tail embryos at a stage prior to the appearance of malformations provides an opportunity to study the morphogenetic processes that precede the development of genetically determined spinal NTD.


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