scholarly journals MiR-324–5p Regulation in Disturbed Embryogenesis Induced by Folate Deficiency

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1279-1279
Author(s):  
Li Wang ◽  
Shao-Yan Chang ◽  
Ting Zhang

Abstract Objectives Folate plays key role during embryogenesis. It is proved that folate deficiency is a risk factor for birth defects mainly exerting its effects through DNA methylation. Here, we want to discover the epigenetic process of DNA methylation in the regulation of miRNAs and thereby regulates neural tube closure through actions on target genes. Methods 40 fetuses with spina bifida and 46 control fetuses from Shanxi Province in China were enrolled to study miR-324–5p alternations with folate deficiency. Meanwhile, mice model with folate deficiency diet were built to study the effects and possible mechanisms of pregnancy folate deficiency. Overexpressed miR-324–5p zebras model were used to detected the role of miR-324–5p during embryogenesis. And disturbed folic acid metabolism cell and mice model were used to confirm the mechanisms of miR-324–5p in neural tube defects induced by folate deficiency. Results We observed decreased miR-324–5p methylation in the brains of individuals with spina bifida. Hypomethylation of miR-324–5 increased the risk of spina bifida, with an odds ratio of 7.0 (95% CI: 2.10–23.36; P < 0.0001). A positive correlation between miR-324–5p methylation and folate levels were verified, and higher folate concentration reversed miR-324–5p alternations. We also observed increased miR-324–5p expression in the folate deficiency group, with concomitant decreased expression of its putative target genes, GLI1 and SMO. Furthermore, overexpression of miR-324–5p induced neural tube defects with inhibition of cell proliferation and migration. Similarly, we confirmed suppression of GLI1 and SMO expression in the brain of individuals with spina bifida. Conclusions The effect of folate deficiency on neural tube development may be mediated by miR-324–5p and its target genes. Funding Sources The National Natural Science Fund of China (81,670,802/H0724), National Key Research and Developmwnt Program (2016YFC1000502).

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Pei Pei ◽  
Xiyue cheng ◽  
Juan Yu ◽  
Jinying Shen ◽  
Xue Li ◽  
...  

Abstract Background Neural tube defects (NTDs) are common congenital malformations resulting in failure of the neural tube closure during early embryonic development. Although it is known that maternal folate deficiency increases the risk of NTDs, the mechanism remains elusive. Results Herein, we report that histone H2A monoubiquitination (H2AK119ub1) plays a role in neural tube closure. We found that the folate antagonist methotrexate induced H2AK119ub1 in mouse embryonic stem cells. We demonstrated that an increase in H2AK119ub1 downregulated expression of the neural tube closure-related genes Cdx2, Nes, Pax6, and Gata4 in mouse embryonic stem cells under folate deficiency conditions. We also determined that the E3 ligase Mdm2 was responsible for the methotrexate-induced increase in H2AK119ub1 and downregulation of neural tube closure-related genes. Surprisingly, we found that Mdm2 is required for MTX-induced H2A ubiquitination and is recruited to the sites of DSB, which is dependent on DNA damage signaling kinase ATM. Furthermore, folic acid supplementation restored H2AK119ub1 binding to neural tube closure-related genes. Downregulation of these genes was also observed in both brain tissue of mouse and human NTD cases, and high levels of H2AK119ub1 were found in the corresponding NTDs samples with their maternal serum folate under low levels. Pearson correlation analysis showed a significant negative correlation between expression of the neural precursor genes and H2AK119ub1. Conclusion Our results indicate that folate deficiency contributes to the onset of NTDs by altering H2AK119ub1 and subsequently affecting expression of neural tube closure-related genes. This may be a potential risk factor for NTDs in response to folate deficiency.


Author(s):  
Jimmy Hoang ◽  
Samuel David Yanofsky

Neural tube defects (NTDs) are congenital abnormalities that arise from the neural tube failing to close. These defects can affect the brain, spine, or spinal cord and generally happen within the first month of pregnancy. Cranial dysraphism is failure of cranial neural tube closure and includes anencephaly and encephalocele. Spinal dysraphism is failure of caudal neuropore closure and includes spina bifida cystica and occulta. Myelomeningocele is a type of spina bifida cystica where the membranous sac containing neural tissue protrudes through an opening in the back. It is the most common NTD and considered a surgical emergency due to the increased risk for infection, further neurologic damage, and dehydration. Advancements in medicine have allowed for the possibility of early diagnosis and even in utero surgical intervention. This chapter focuses more exclusively on the approach and management of myelomeningocele.


2007 ◽  
Vol 31 (2) ◽  
pp. 244-251 ◽  
Author(s):  
Courtney E. Davidson ◽  
Qian Li ◽  
Gary A. Churchill ◽  
Lucy R. Osborne ◽  
Heather E. McDermid

Neural tube defects (NTDs), the second most common birth defect in humans, are multifactorial with complex genetic and environmental causes, although the genetic factors are almost completely unknown. In mice, >100 single gene mutations cause NTDs; however, the penetrance in many of these single gene mutant lines is highly dependent on the genetic background. We previously reported that a homozygous Cecr2 mutation on a BALB/c background causes exencephaly at a frequency of 74% compared with 0% on an FVB/N background. We now report that a major genetic modifier on chromosome 19, mapped using whole genome linkage analysis, increases the relative risk of exencephaly by 3.74 times in homozygous BALB embryos vs. BALB/FVB heterozygotes. Scanning electron microscopy revealed that the modifier does not affect the location of neural tube closure site 2, a known murine susceptibility factor for exencephaly. Crossing the Sp ( Splotch) mutation in the Pax3 gene onto the FVB/N background for two generations indicated that this resistant strain also decreases the penetrance of spina bifida. The chromosome 19 modifier region corresponds to a linkage region on human chromosome 10q25.3 mapped in a whole genome scan of human NTD families. Since the FVB/N genetic background affects susceptibility to both exencephaly and spina bifida, the human homolog of the chromosome 19 modifier locus may be a better candidate for human NTD susceptibility factors than genes that when mutated actually cause NTDs in mice.


2019 ◽  
Author(s):  
Ana Rolo ◽  
Gabriel L. Galea ◽  
Dawn Savery ◽  
Nicholas D. E. Greene ◽  
Andrew J. Copp

ABSTRACTEncephalocele is a clinically important birth defect that can lead to severe disability in childhood and beyond. The embryonic pathogenesis of encephalocele is poorly understood and, while usually classified as a ‘neural tube defect’, there is conflicting evidence on whether encephalocele results from defective neural tube closure, or is a post-neurulation defect. It is also unclear whether encephalocele can result from the same causative factors as anencephaly and open spina bifida, or whether it is aetiologically distinct. This lack of information results largely from the scarce availability of animal models of encephalocele, particularly ones that resemble the commonest, non-syndromic human defects. Here we report a novel mouse model of occipito-parietal encephalocele, in which the small GTPase Rac1 is conditionally ablated in the (non-neural) surface ectoderm. Most mutant fetuses have open spina bifida, and some also exhibit exencephaly/anencephaly. However, a large proportion of mutant fetuses exhibit encephalocele affecting the occipito-parietal region. The encephalocele phenotype does not result from a defect in neural tube closure, but rather from a later disruption of the surface ectoderm covering the already closed neural tube, allowing the brain to herniate. The neuroepithelium itself shows no down-regulation of Rac1 and appears morphologically normal until late gestation. A large skull defect develops overlying the region of brain herniation. Our work provides a new genetic model of occipito-parietal encephalocele, particularly resembling non-syndromic human cases. While encephalocele has a different, later-arising pathogenesis than open neural tube defects, both can share the same genetic causation.SUMMARY STATEMENTEncephalocele - a severe brain defect - arises after neural tube closure, but can share a common genetic cause with anencephaly, a defect of neural tube closure.


Author(s):  
K.K. Otaryan , C.G. Gagaev

The case of prenatal detection of spina bifida at 12+3 weeks of gestation is described. Termination of pregnancy was performed at 13+3 weeks. Post-abortion karyotyping revealed triploidy (69XXX). Diagnostic tools for early detection of neural tube defects in the 1st trimester of gestation and subsequent appropriate management of pregnancy are discussed.


2008 ◽  
Vol 17 (23) ◽  
pp. 3675-3685 ◽  
Author(s):  
K. A. Burren ◽  
D. Savery ◽  
V. Massa ◽  
R. M. Kok ◽  
J. M. Scott ◽  
...  

2021 ◽  
Vol 1 (12) ◽  
pp. 896-903
Author(s):  
Genta Faesal Atsani ◽  
Zanetha Mauly Ilawanda ◽  
Ilma Fahira Basyir

Neural tube defects (NTD) are one of the birth defects or congenital abnormalities that occur in the brain and spine, and commonly find in newborns worldwide. Anencephaly and spina bifida are the two prevalent forms of NTD. The incidence of spina bifida happen on average 1 in 1000 cases of birth worldwide and there are 140,000 cases per year worldwide. Source searches were carried out on the online portal of journal publications as many as 20 sources from MedScape, Google Scholar and the Nation Center for Biotechnology Information / NCBI with the keywords “Neural tube defects (NTD), prevention, and spina bifida”. Spina bifida is a congenital abnormality that occurs in the womb due to a failure of closing process the neural tube during the first few weeks of embryonic development which causes the spine not completely close around the developing spinal cord nerves. NTD can ensue multifactorial conditions such as genetic, environmental, and folate deficiency. The use of folic acid supplementation starting at least 3 months before pregnancy, those are 400 mcg (0.4 mg) per day and 800 mcg per day during pregnancy can reduce the risk of developing neural tube defects such as spina bifida. Generally, spina bifida is undertaking by surgery and the regulation of patients comorbid. Public can find out prevention to avoid or reduce the risk of spina bifida so that the incidence of spina bifida can decrease along with the increasing awareness of the community regarding this disease.


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