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Wang S, Zeng Y, He X, Liu F, Pei P, Zhang T. Folate-deficiency induced acyl-CoA synthetase short-chain family member 2 increases lysine crotonylome involved in neural tube defects. Front Mol Neurosci 2023; 15:1064509. [PMID: 36743291 PMCID: PMC9895841 DOI: 10.3389/fnmol.2022.1064509] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 12/28/2022] [Indexed: 01/22/2023] Open
Abstract
Maternal folate deficiency increases the risk of neural tube defects (NTDs), but the mechanism remains unclear. Here, we established a mouse model of NTDs via low folate diets combined with MTX-induced conditions. We found that a significant increase in butyrate acid was observed in mouse NTDs brains. In addition, aberrant key crotonyl-CoA-producing enzymes acyl-CoA synthetase short-chain family member 2 (ACSS2) levels and lysine crotonylation (Kcr) were elevated high in corresponding low folate content maternal serum samples from mouse NTD model. Next, proteomic analysis revealed that folate deficiency led to global proteomic modulation, especially in key crotonyl-CoA-producing enzymes, and dramatic ultrastructural changes in mouse embryonic stem cells (mESCs). Furthermore, we determined that folate deficiency induced ACSS2 and Kcr in mESCs. Surprisingly, folic acid supplementation restored level of ACSS2 and Kcr. We also investigated overall protein post-translational Kcr under folate deficiency, revealing the key regulation of Kcr in glycolysis/gluconeogenesis, and the citric acid cycle. Our findings suggest folate deficiency leads to the occurrence of NTDs by altering ACSS2. Protein crotonylation may be the molecular basis for NTDs remodeling by folate deficiency.
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Affiliation(s)
- Shan Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China,Capital Institute of Pediatrics-Peking University Teaching Hospital, Beijing, China,Graduate School of Peking Union Medical College, Capital Institute of Pediatrics, Beijing, China,*Correspondence: Shan Wang, ; Ting Zhang,
| | - Yubing Zeng
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
| | - Xuejia He
- Capital Institute of Pediatrics-Peking University Teaching Hospital, Beijing, China
| | - Fan Liu
- Graduate School of Peking Union Medical College, Capital Institute of Pediatrics, Beijing, China
| | - Pei Pei
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
| | - Ting Zhang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China,Capital Institute of Pediatrics-Peking University Teaching Hospital, Beijing, China,Graduate School of Peking Union Medical College, Capital Institute of Pediatrics, Beijing, China,*Correspondence: Shan Wang, ; Ting Zhang,
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2
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Kakebeen AD, Niswander L. Micronutrient imbalance and common phenotypes in neural tube defects. Genesis 2021; 59:e23455. [PMID: 34665506 PMCID: PMC8599664 DOI: 10.1002/dvg.23455] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/31/2021] [Accepted: 09/03/2021] [Indexed: 12/24/2022]
Abstract
Neural tube defects (NTDs) are among the most common birth defects, with a prevalence of close to 19 per 10,000 births worldwide. The etiology of NTDs is complex involving the interplay of genetic and environmental factors. Since nutrient deficiency is a risk factor and dietary changes are the major preventative measure to reduce the risk of NTDs, a more detailed understanding of how common micronutrient imbalances contribute to NTDs is crucial. While folic acid has been the most discussed environmental factor due to the success that population-wide fortification has had on prevention of NTDs, folic acid supplementation does not prevent all NTDs. The imbalance of several other micronutrients has been implicated as risks for NTDs by epidemiological studies and in vivo studies in animal models. In this review, we highlight recent literature deciphering the multifactorial mechanisms underlying NTDs with an emphasis on mouse and human data. Specifically, we focus on advances in our understanding of how too much or too little retinoic acid, zinc, and iron alter gene expression and cellular processes contributing to the pathobiology of NTDs. Synthesis of the discussed literature reveals common cellular phenotypes found in embryos with NTDs resulting from several micronutrient imbalances. The goal is to combine knowledge of these common cellular phenotypes with mechanisms underlying micronutrient imbalances to provide insights into possible new targets for preventative measures against NTDs.
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Affiliation(s)
- Anneke Dixie Kakebeen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Lee Niswander
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
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3
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Craenen K, Verslegers M, Callaerts-Vegh Z, Craeghs L, Buset J, Govaerts K, Neefs M, Gsell W, Baatout S, D'Hooge R, Himmelreich U, Moons L, Benotmane MA. Folic Acid Fortification Prevents Morphological and Behavioral Consequences of X-Ray Exposure During Neurulation. Front Behav Neurosci 2021; 14:609660. [PMID: 33488367 PMCID: PMC7820780 DOI: 10.3389/fnbeh.2020.609660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/08/2020] [Indexed: 12/02/2022] Open
Abstract
Previous studies suggested a causal link between pre-natal exposure to ionizing radiation and birth defects such as microphthalmos and exencephaly. In mice, these defects arise primarily after high-dose X-irradiation during early neurulation. However, the impact of sublethal (low) X-ray doses during this early developmental time window on adult behavior and morphology of central nervous system structures is not known. In addition, the efficacy of folic acid (FA) in preventing radiation-induced birth defects and persistent radiation-induced anomalies has remained unexplored. To assess the efficacy of FA in preventing radiation-induced defects, pregnant C57BL6/J mice were X-irradiated at embryonic day (E)7.5 and were fed FA-fortified food. FA partially prevented radiation-induced (1.0 Gy) anophthalmos, exencephaly and gastroschisis at E18, and reduced the number of pre-natal deaths, fetal weight loss and defects in the cervical vertebrae resulting from irradiation. Furthermore, FA food fortification counteracted radiation-induced impairments in vision and olfaction, which were evidenced after exposure to doses ≥0.1 Gy. These findings coincided with the observation of a reduction in thickness of the retinal ganglion cell and nerve fiber layer, and a decreased axial length of the eye following exposure to 0.5 Gy. Finally, MRI studies revealed a volumetric decrease of the hippocampus, striatum, thalamus, midbrain and pons following 0.5 Gy irradiation, which could be partially ameliorated after FA food fortification. Altogether, our study is the first to offer detailed insights into the long-term consequences of X-ray exposure during neurulation, and supports the use of FA as a radioprotectant and antiteratogen to counter the detrimental effects of X-ray exposure during this crucial period of gestation.
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Affiliation(s)
- Kai Craenen
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (Studiecentrum voor Kernenergie; Centre d'étude de l'énergie nucléaire), Mol, Belgium
- Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology Section, Department of Biology, Faculty of Science, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Mieke Verslegers
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (Studiecentrum voor Kernenergie; Centre d'étude de l'énergie nucléaire), Mol, Belgium
| | - Zsuzsanna Callaerts-Vegh
- Laboratory of Biological Psychology, Faculty of Psychology and Educational Sciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Livine Craeghs
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (Studiecentrum voor Kernenergie; Centre d'étude de l'énergie nucléaire), Mol, Belgium
- Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology Section, Department of Biology, Faculty of Science, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Jasmine Buset
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (Studiecentrum voor Kernenergie; Centre d'étude de l'énergie nucléaire), Mol, Belgium
| | - Kristof Govaerts
- Molecular Small Animal Imaging Center, Biomedical MRI Unit, Department of Imaging and Pathology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Mieke Neefs
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (Studiecentrum voor Kernenergie; Centre d'étude de l'énergie nucléaire), Mol, Belgium
| | - Willy Gsell
- Molecular Small Animal Imaging Center, Biomedical MRI Unit, Department of Imaging and Pathology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Sarah Baatout
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (Studiecentrum voor Kernenergie; Centre d'étude de l'énergie nucléaire), Mol, Belgium
| | - Rudi D'Hooge
- Laboratory of Biological Psychology, Faculty of Psychology and Educational Sciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Uwe Himmelreich
- Molecular Small Animal Imaging Center, Biomedical MRI Unit, Department of Imaging and Pathology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Lieve Moons
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (Studiecentrum voor Kernenergie; Centre d'étude de l'énergie nucléaire), Mol, Belgium
- Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology Section, Department of Biology, Faculty of Science, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Mohammed Abderrafi Benotmane
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (Studiecentrum voor Kernenergie; Centre d'étude de l'énergie nucléaire), Mol, Belgium
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4
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Abstract
During embryonic development, the central nervous system forms as the neural plate and then rolls into a tube in a complex morphogenetic process known as neurulation. Neural tube defects (NTDs) occur when neurulation fails and are among the most common structural birth defects in humans. The frequency of NTDs varies greatly anywhere from 0.5 to 10 in 1000 live births, depending on the genetic background of the population, as well as a variety of environmental factors. The prognosis varies depending on the size and placement of the lesion and ranges from death to severe or moderate disability, and some NTDs are asymptomatic. This chapter reviews how mouse models have contributed to the elucidation of the genetic, molecular, and cellular basis of neural tube closure, as well as to our understanding of the causes and prevention of this devastating birth defect.
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Affiliation(s)
- Irene E Zohn
- Center for Genetic Medicine, Children's Research Institute, Children's National Medical Center, Washington, DC, USA.
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5
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Park HS, Kim JO, An HJ, Ryu CS, Ko EJ, Kim YR, Ahn EH, Lee WS, Kim JH, Kim NK. Genetic polymorphisms of the cobalamin transport system are associated with idiopathic recurrent implantation failure. J Assist Reprod Genet 2019; 36:1513-1522. [PMID: 31123954 DOI: 10.1007/s10815-019-01455-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/16/2019] [Indexed: 12/15/2022] Open
Abstract
PURPOSE Vitamin B12 (cobalamin, Cbl) plays a role in the recycling of folate, which is important in pregnancy. Transcobalamin II (TCN2) and transcobalamin receptor (TCblR) proteins are involved in the cellular uptake of Cbl. TCN2 binds Cbl in the plasma, and TCblR binds TCN2-Cbl at the cell surface. Therefore, we investigated the potential association between polymorphisms in Cbl transport proteins, TCN2 and TCblR, and recurrent implantation failure (RIF) susceptibility. METHODS The genotypes of TCN2 67A>G, TCN2 776C>G, and TCblR 1104C>T were determined for RIF patients and healthy controls using a polymerase chain reaction restriction fragment length polymorphism assay. Additionally, statistical analysis was performed to compare the genotype frequencies between RIF patients and controls. RESULTS The TCN2 67 polymorphism AG type was associated with RIF risk. Some allele combinations that contained the TCN2 67 polymorphism G allele were associated with increased RIF risk, whereas other allele combinations that contained the TCblR 1104 polymorphism T alleles were associated with decreased RIF risk. In genotype combination analysis, two combinations containing the TCN2 67 polymorphism AG type were associated with RIF risk. CONCLUSION Our study showed that the polymorphisms of TCN2 and TCblR are associated with RIF and are potential genetic predisposing factors for RIF among Korean women. Additionally, our findings support a potential role for TCN2 and TCblR in RIF among Korean women. However, further studies are required to investigate the role of the polymorphisms in those proteins and RIF because the roles of the TCN2 and TCblR polymorphisms in RIF are not clear.
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Affiliation(s)
- Han Sung Park
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Jung Oh Kim
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Hui Jeong An
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Chang Soo Ryu
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Eun Ju Ko
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Young Ran Kim
- Department of Obstetrics and Gynecology, CHA Bundang Medical Center, CHA University, 11, Yatap-ro 65beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Eun Hee Ahn
- Department of Obstetrics and Gynecology, CHA Bundang Medical Center, CHA University, 11, Yatap-ro 65beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Woo Sik Lee
- Fertility Center of CHA Gangnam Medical Center, CHA University, 566, Nonhyeon-ro, Gangnam-gu, Seoul, 06135, Republic of Korea
| | - Ji Hyang Kim
- Department of Obstetrics and Gynecology, CHA Bundang Medical Center, CHA University, 11, Yatap-ro 65beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea.
| | - Nam Keun Kim
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea.
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6
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Martin JB, Muccioli M, Herman K, Finnell RH, Plageman TF. Folic acid modifies the shape of epithelial cells during morphogenesis via a Folr1 and MLCK dependent mechanism. Biol Open 2019; 8:8/1/bio041160. [PMID: 30670450 PMCID: PMC6361208 DOI: 10.1242/bio.041160] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Folic acid supplementation can prevent neural tube defects, but the specific molecular mechanisms by which it does have not been elucidated. During neural plate morphogenesis, epithelial cell apical constriction cooperates with other events to drive tissue-bending, and when defective, can result in neural tube defects. A Rho-kinase deficient binding mutant of the apical constriction regulating protein, Shroom3 (Shroom3R1838C), is one of only a handful of mouse mutant lines with neural tube defects that can be rescued by folic acid supplementation. This provided a unique opportunity to probe the functional rescue of a protein linked to neural tube development by folic acid. Utilizing an epithelial cell culture model of apical constriction, it was observed that treatment with exogenous folic acid, as well as co-expression of the folic acid receptor Folr1, can rescue the function of the Rho-kinase binding deficient mutant of Shroom3 in vitro It was also determined that the rescuing ability of folic acid is RhoA and Rho-kinase independent but myosin light chain kinase (MLCK) and Src-kinase dependent. Inhibition of Rho-kinase-dependent apical constriction in chick embryo neural epithelium was also observed to be rescued by exogenous folic acid and that treatment with folic acid is accompanied by elevated activated myosin light chain and MLCK. Furthermore, doubly heterozygous mouse embryos lacking one copy each of Shroom3 and Folr1 exhibit a low rate of neural tube defects and also have lower levels of activated myosin light chain and MLCK. These studies suggest a novel mechanism by which folic acid modifies epithelial cell shape during morphogenesis, shedding light onto how folic acid may prevent neural tube defects.
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Affiliation(s)
- Jessica B Martin
- The Ohio State University, College of Optometry, Columbus, OH 43210, USA
| | - Maria Muccioli
- The Ohio State University, College of Optometry, Columbus, OH 43210, USA
| | - Kenneth Herman
- The Ohio State University, College of Optometry, Columbus, OH 43210, USA
| | - Richard H Finnell
- Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Timothy F Plageman
- The Ohio State University, College of Optometry, Columbus, OH 43210, USA
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7
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Insights into the Etiology of Mammalian Neural Tube Closure Defects from Developmental, Genetic and Evolutionary Studies. J Dev Biol 2018; 6:jdb6030022. [PMID: 30134561 PMCID: PMC6162505 DOI: 10.3390/jdb6030022] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 08/13/2018] [Accepted: 08/15/2018] [Indexed: 02/06/2023] Open
Abstract
The human neural tube defects (NTD), anencephaly, spina bifida and craniorachischisis, originate from a failure of the embryonic neural tube to close. Human NTD are relatively common and both complex and heterogeneous in genetic origin, but the genetic variants and developmental mechanisms are largely unknown. Here we review the numerous studies, mainly in mice, of normal neural tube closure, the mechanisms of failure caused by specific gene mutations, and the evolution of the vertebrate cranial neural tube and its genetic processes, seeking insights into the etiology of human NTD. We find evidence of many regions along the anterior–posterior axis each differing in some aspect of neural tube closure—morphology, cell behavior, specific genes required—and conclude that the etiology of NTD is likely to be partly specific to the anterior–posterior location of the defect and also genetically heterogeneous. We revisit the hypotheses explaining the excess of females among cranial NTD cases in mice and humans and new developments in understanding the role of the folate pathway in NTD. Finally, we demonstrate that evidence from mouse mutants strongly supports the search for digenic or oligogenic etiology in human NTD of all types.
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8
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Stokes BA, Sabatino JA, Zohn IE. High levels of iron supplementation prevents neural tube defects in the Fpn1 ffe mouse model. Birth Defects Res 2018; 109:81-91. [PMID: 28008752 DOI: 10.1002/bdra.23542] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 05/11/2016] [Accepted: 06/05/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND Periconception maternal nutrition and folate in particular are important factors influencing the incidence of neural tube defects (NTDs). Many but not all NTDs are prevented by folic acid supplementation and there is a pressing need for additional strategies to prevent these birth defects. Other micronutrients such as iron are potential candidates, yet a clear role for iron deficiency in contributing to NTDs is lacking. Our previous studies with the flatiron (ffe) mouse model of Ferroportin1 (Fpn1) deficiency suggest that iron is required for neural tube closure and forebrain development raising the possibility that iron supplementation could prevent NTDs. METHODS We determined the effect of periconception iron and/or folic acid supplementation on the penetrance of NTDs in the Fpn1ffe mouse model. Concurrently, measurements of folate and iron were made to ensure supplementation had the intended effects. RESULTS High levels of iron supplementation significantly reduced the incidence of NTDs in Fpn1ffe mutants. Fpn1 deficiency resulted in reduced folate levels in both pregnant dams and embryos. Yet folic acid supplementation did not prevent NTDs in the Fpn1ffe model. Similarly, forebrain truncations were rescued with iron. Surprisingly, the high levels of iron supplementation used in this study caused folate deficiency in wild-type dams and embryos. CONCLUSION Our results demonstrate that iron supplementation can prevent NTDs and forebrain truncations in the Fpn1ffe model. Surprisingly, high levels of iron supplementation and iron overload can cause folate deficiency. If iron is essential for neural tube closure, it is possible that iron deficiency might contribute to NTDs. Birth Defects Research 109:81-91, 2017. © 2016 The Authors Birth Defects Research Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Bethany A Stokes
- Department of Biology, The George Washington University, Washington, DC.,Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC
| | - Julia A Sabatino
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC
| | - Irene E Zohn
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC
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9
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Gao X, Finnell RH, Wang H, Zheng Y. Network correlation analysis revealed potential new mechanisms for neural tube defects beyond folic acid. Birth Defects Res 2018; 110:982-993. [PMID: 29732722 DOI: 10.1002/bdr2.1336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 12/28/2022]
Abstract
BACKGROUND Neural tube defects (NTDs) are clinically significant congenital malformations which are known to be folic acid (FA) responsive, such that supplementation significantly reduces the prevalence of NTDs. Nonetheless, some individuals fail to respond to FA supplementation; hence NTDs remain a significant public health concern. The mechanisms that underlie the beneficial effects of FA supplementation remain poorly understood. Mouse models have been used extensively to study the mechanisms driving neural tube closure (NTC). METHODS Microarray data of GSE51285 was downloaded from the NCBI GEO database, which contains the RNA expression profiles of livers from five NTD mouse mutants (heterozygous females) and their corresponding wildtype (WT) controls. Those five NTD mutants have different responsiveness to FA supplementation. The differentially expressed genes (DEGs) between NTD heterozygous and WT mice, as well as the DEGs between FA-responsive and FA-resistant mutants were carefully examined. Weighted gene correlation network analysis (WGCNA) was performed in order to identify genes with high correlations to either FA responsiveness or NTDs, respectively. RESULTS In total, we identified 18 genes related to the pathogenesis of NTDs, as well as 55 genes related to FA responsiveness. Eight more candidate genes (Abcc3, Gsr, Gclc, Mthfd1, Gart, Bche, Slc25a32, and Slc44a2) were identified by examining the DEGs of those genes involved in the extended folate metabolic pathway between FA-responsive and FA-resistant mutants. CONCLUSIONS Those genes are involved in mitochondrial choline metabolism, de novo purine synthesis, and glutathione generation, suggesting that formate, choline, and manipulating antioxidant levels may be effective interventions in FA-resistant NTDs.
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Affiliation(s)
- Xiaoya Gao
- Institute of Developmental Biology & Molecular Medicine, School of Life Sciences, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Richard H Finnell
- Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas.,Collaborative Innovation Center for Genetics & Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Hongyan Wang
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
| | - Yufang Zheng
- Institute of Developmental Biology & Molecular Medicine, School of Life Sciences, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
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10
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Sabatino JA, Stokes BA, Zohn IE. Prevention of neural tube defects in Lrp2 mutant mouse embryos by folic acid supplementation. Birth Defects Res 2018; 109:16-26. [PMID: 27883261 DOI: 10.1002/bdra.23589] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 09/18/2016] [Indexed: 01/03/2023]
Abstract
BACKGROUND Neural tube defects (NTDs) are among the most common structural birth defects in humans and are caused by the complex interaction of genetic and environmental factors. Periconceptional supplementation with folic acid can prevent NTDs in both mouse models and human populations. A better understanding of how genes and environmental factors interact is critical toward development of rational strategies to prevent NTDs. Low density lipoprotein-related protein 2 (Lrp2) is involved in endocytosis of the folic acid receptor among numerous other nutrients and ligands. METHODS We determined the effect of iron and/or folic acid supplementation on the penetrance of NTDs in the Lrp2null mouse model. The effects of supplementation on folate and iron status were measured in embryos and dams. RESULTS Periconceptional dietary supplementation with folic acid did not prevent NTDs in Lrp2 mutant embryos, whereas high levels of folic acid supplementation by intraperitoneal injection reduced incidence of NTDs. Importantly, Lrp2null/+ dams had reduced blood folate levels that improved with daily intraperitoneal injections of folate but not dietary supplementation. On the contrary, iron supplementation had no effect on the penetrance of NTDs in Lrp2 mutant embryos and negated the preventative effect of folic acid supplementation in Lrp2null/null mutants. CONCLUSION Lrp2 is required for folate homeostasis in heterozygous dams and high levels of supplementation prevents NTDs. Furthermore, high levels of dietary iron supplementation interfered with folic acid supplementation negating the positive effects of supplementation in this model. Birth Defects Research 109:16-26, 2017. © 2016 The Authors Birth Defects Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Julia A Sabatino
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC
| | - Bethany A Stokes
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC.,Department of Biology, The George Washington University, Washington, DC
| | - Irene E Zohn
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC
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11
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Au KS, Findley TO, Northrup H. Finding the genetic mechanisms of folate deficiency and neural tube defects-Leaving no stone unturned. Am J Med Genet A 2017; 173:3042-3057. [PMID: 28944587 PMCID: PMC5650505 DOI: 10.1002/ajmg.a.38478] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 08/11/2017] [Accepted: 08/21/2017] [Indexed: 12/21/2022]
Abstract
Neural tube defects (NTDs) occur secondary to failed closure of the neural tube between the third and fourth weeks of gestation. The worldwide incidence ranges from 0.3 to 200 per 10,000 births with the United States of American NTD incidence at around 3-6.3 per 10,000 dependent on race and socioeconomic background. Human NTD incidence has fallen by 35-50% in North America due to mandatory folic acid fortification of enriched cereal grain products since 1998. The US Food and Drug Administration has approved the folic acid fortification of corn masa flour with the goal to further reduce the incidence of NTDs, especially among individuals who are Hispanic. However, the genetic mechanisms determining who will benefit most from folate enrichment of the diet remains unclear despite volumes of literature published on studies of association of genes with functions related to folate metabolism and risk of human NTDs. The advances in omics technologies provides hypothesis-free tools to interrogate every single gene within the genome of NTD affected individuals to discover pathogenic variants and methylation targets throughout the affected genome. By identifying genes with expression regulated by presence of folate through transcriptome profiling studies, the genetic mechanisms leading to human NTDs due to folate deficiency may begin to be more efficiently revealed.
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Affiliation(s)
- KS Au
- Division of Medical Genetics, Department of Pediatrics, University of Texas Health Science Houston – McGovern Medical School, Houston, TX
| | - TO Findley
- Division of Neonatology, Department of Pediatrics, University of Texas Health Science Houston – McGovern Medical School, Houston, TX
| | - H Northrup
- Division of Medical Genetics, Department of Pediatrics, University of Texas Health Science Houston – McGovern Medical School, Houston, TX
- Shriners Hospitals for Children - Houston, Houston, TX
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12
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Anderson MJ, Schimmang T, Lewandoski M. An FGF3-BMP Signaling Axis Regulates Caudal Neural Tube Closure, Neural Crest Specification and Anterior-Posterior Axis Extension. PLoS Genet 2016; 12:e1006018. [PMID: 27144312 PMCID: PMC4856314 DOI: 10.1371/journal.pgen.1006018] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 04/08/2016] [Indexed: 01/08/2023] Open
Abstract
During vertebrate axis extension, adjacent tissue layers undergo profound morphological changes: within the neuroepithelium, neural tube closure and neural crest formation are occurring, while within the paraxial mesoderm somites are segmenting from the presomitic mesoderm (PSM). Little is known about the signals between these tissues that regulate their coordinated morphogenesis. Here, we analyze the posterior axis truncation of mouse Fgf3 null homozygotes and demonstrate that the earliest role of PSM-derived FGF3 is to regulate BMP signals in the adjacent neuroepithelium. FGF3 loss causes elevated BMP signals leading to increased neuroepithelium proliferation, delay in neural tube closure and premature neural crest specification. We demonstrate that elevated BMP4 depletes PSM progenitors in vitro, phenocopying the Fgf3 mutant, suggesting that excessive BMP signals cause the Fgf3 axis defect. To test this in vivo we increased BMP signaling in Fgf3 mutants by removing one copy of Noggin, which encodes a BMP antagonist. In such mutants, all parameters of the Fgf3 phenotype were exacerbated: neural tube closure delay, premature neural crest specification, and premature axis termination. Conversely, genetically decreasing BMP signaling in Fgf3 mutants, via loss of BMP receptor activity, alleviates morphological defects. Aberrant apoptosis is observed in the Fgf3 mutant tailbud. However, we demonstrate that cell death does not cause the Fgf3 phenotype: blocking apoptosis via deletion of pro-apoptotic genes surprisingly increases all Fgf3 defects including causing spina bifida. We demonstrate that this counterintuitive consequence of blocking apoptosis is caused by the increased survival of BMP-producing cells in the neuroepithelium. Thus, we show that FGF3 in the caudal vertebrate embryo regulates BMP signaling in the neuroepithelium, which in turn regulates neural tube closure, neural crest specification and axis termination. Uncovering this FGF3-BMP signaling axis is a major advance toward understanding how these tissue layers interact during axis extension with important implications in human disease. During embryological development, the vertebrate embryo undergoes profound growth in a head-to-tail direction. During this process, formation of different structures within adjacent tissue layers must occur in a coordinated fashion. Insights into how these adjacent tissues molecularly communicate with each other is essential to understanding both basic embryology and the underlying causes of human birth defects. Mice lacking Fgf3, which encodes a secreted signaling factor, have long been known to have premature axis termination, but the underlying mechanism has not been studied until now. Through a series of complex genetic experiments, we show that FGF3 is an essential factor for coordination of neural tube development and axis extension. FGF3 is secreted from the mesodermal layer, which is the major driver of extending the axis, and negatively regulates expression of another class of secreted signaling molecules in the neuroepithelium, BMPs. In the absence of FGF3, excessive BMP signals cause a delay in neural tube closure, premature specification of neural crest cells and negatively affect the mesoderm, causing a premature termination of the embryological axis. Our work suggests that FGF3 may be a player in the complex etiology of the human birth defect, spina bifida, the failure of posterior neural tube closure.
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Affiliation(s)
- Matthew J. Anderson
- Genetics of Vertebrate Development Section, Cancer and Developmental Biology Lab, National Cancer Institute, National Institutes of Health, Frederick, Maryland, United States of America
| | - Thomas Schimmang
- Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, Valladolid, Spain
| | - Mark Lewandoski
- Genetics of Vertebrate Development Section, Cancer and Developmental Biology Lab, National Cancer Institute, National Institutes of Health, Frederick, Maryland, United States of America
- * E-mail:
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Identifying Regulators of Morphogenesis Common to Vertebrate Neural Tube Closure and Caenorhabditis elegans Gastrulation. Genetics 2015; 202:123-39. [PMID: 26434722 DOI: 10.1534/genetics.115.183137] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 09/29/2015] [Indexed: 12/18/2022] Open
Abstract
Neural tube defects including spina bifida are common and severe congenital disorders. In mice, mutations in more than 200 genes can result in neural tube defects. We hypothesized that this large gene set might include genes whose homologs contribute to morphogenesis in diverse animals. To test this hypothesis, we screened a set of Caenorhabditis elegans homologs for roles in gastrulation, a topologically similar process to vertebrate neural tube closure. Both C. elegans gastrulation and vertebrate neural tube closure involve the internalization of surface cells, requiring tissue-specific gene regulation, actomyosin-driven apical constriction, and establishment and maintenance of adhesions between specific cells. Our screen identified several neural tube defect gene homologs that are required for gastrulation in C. elegans, including the transcription factor sptf-3. Disruption of sptf-3 in C. elegans reduced the expression of early endodermally expressed genes as well as genes expressed in other early cell lineages, establishing sptf-3 as a key contributor to multiple well-studied C. elegans cell fate specification pathways. We also identified members of the actin regulatory WAVE complex (wve-1, gex-2, gex-3, abi-1, and nuo-3a). Disruption of WAVE complex members reduced the narrowing of endodermal cells' apical surfaces. Although WAVE complex members are expressed broadly in C. elegans, we found that expression of a vertebrate WAVE complex member, nckap1, is enriched in the developing neural tube of Xenopus. We show that nckap1 contributes to neural tube closure in Xenopus. This work identifies in vivo roles for homologs of mammalian neural tube defect genes in two manipulable genetic model systems.
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Zheng J, Lu X, Liu H, Zhao P, Li K, Li L. MTHFD1 polymorphism as maternal risk for neural tube defects: a meta-analysis. Neurol Sci 2014; 36:607-16. [PMID: 25502174 DOI: 10.1007/s10072-014-2035-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 12/06/2014] [Indexed: 11/27/2022]
Abstract
Recently, the association between methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) G1958A polymorphism and neural tube defects (NTD) susceptibility has been widely investigated; however, the results remained inconclusive. Hence, we conducted a meta-analysis to evaluate the effect of MTHFD1 G1958A polymorphism on NTD. The relative literatures were identified by search of the electronic databases PubMed, MEDLINE, and EMBASE. The extracted data were statistically analyzed, and pooled odds ratios (ORs) with 95 % confidence intervals (CIs) were calculated to estimate the association strength using Stata version 11.0 software. Finally, ten studies met our inclusion criteria, including 2,132/4,082 in NTD infants and controls; 1,402/3,136 in mothers with NTD offspring and controls; and 993/2,879 in fathers with NTD offspring and controls. This meta-analysis showed that, compared with the mothers with GG genotype, the women with AA genotype had an increased risk of NTD in their offspring, with OR values and 95 % CI at 1.39 (1.16-1.68), p < 0.001. Interestingly, fathers with AG genotype had a significant decreased risk of NTD offspring (OR = 0.79, 95 % CI = 0.66-0.94, p = 0.009). However, there was no significant association between the MTHFD1 G1958A polymorphism in NTD patients and the risk of NTD. In conclusion, the present meta-analysis provided evidence of the association between maternal MTHFD1 G1958A polymorphism and NTD susceptibility.
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Affiliation(s)
- Jinyu Zheng
- Department of Neurosurgery, First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, 210029, Jiangsu, People's Republic of China
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15
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Wilde JJ, Petersen JR, Niswander L. Genetic, epigenetic, and environmental contributions to neural tube closure. Annu Rev Genet 2014; 48:583-611. [PMID: 25292356 DOI: 10.1146/annurev-genet-120213-092208] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The formation of the embryonic brain and spinal cord begins as the neural plate bends to form the neural folds, which meet and adhere to close the neural tube. The neural ectoderm and surrounding tissues also coordinate proliferation, differentiation, and patterning. This highly orchestrated process is susceptible to disruption, leading to neural tube defects (NTDs), a common birth defect. Here, we highlight genetic and epigenetic contributions to neural tube closure. We describe an online database we created as a resource for researchers, geneticists, and clinicians. Neural tube closure is sensitive to environmental influences, and we discuss disruptive causes, preventative measures, and possible mechanisms. New technologies will move beyond candidate genes in small cohort studies toward unbiased discoveries in sporadic NTD cases. This will uncover the genetic complexity of NTDs and critical gene-gene interactions. Animal models can reveal the causative nature of genetic variants, the genetic interrelationships, and the mechanisms underlying environmental influences.
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Affiliation(s)
- Jonathan J Wilde
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Children's Hospital Colorado, Aurora, Colorado 80045;
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16
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Momb J, Appling DR. Mitochondrial one-carbon metabolism and neural tube defects. ACTA ACUST UNITED AC 2014; 100:576-83. [PMID: 24985542 DOI: 10.1002/bdra.23268] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/02/2014] [Accepted: 05/19/2014] [Indexed: 11/08/2022]
Abstract
BACKGROUND Neural tube defects (NTDs) are one of the most common birth defects in humans. Maternal intake of folic acid was linked to prevention of NTDs in the 1970s. This realization led to the establishment of mandatory and/or voluntary food folic acid fortification programs in many countries that have reduced the incidence of NTDs by up to 70% in humans. Despite 40 years of intensive research, the biochemical mechanisms underlying the protective effects of folic acid remain unknown. RESULTS Recent research reveals a role for mitochondrial folate-dependent one-carbon metabolism in neural tube closure. CONCLUSION In this article, we review the evidence linking NTDs to aberrant mitochondrial one-carbon metabolism in humans and mouse models. The potential of formate, a product of mitochondrial one-carbon metabolism, to prevent NTDs is also discussed.
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Affiliation(s)
- Jessica Momb
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas
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17
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Kappen C. Modeling anterior development in mice: diet as modulator of risk for neural tube defects. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2013; 163C:333-56. [PMID: 24124024 PMCID: PMC4149464 DOI: 10.1002/ajmg.c.31380] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Head morphogenesis is a complex process that is controlled by multiple signaling centers. The most common defects of cranial development are craniofacial defects, such as cleft lip and cleft palate, and neural tube defects, such as anencephaly and encephalocoele in humans. More than 400 genes that contribute to proper neural tube closure have been identified in experimental animals, but only very few causative gene mutations have been identified in humans, supporting the notion that environmental influences are critical. The intrauterine environment is influenced by maternal nutrition, and hence, maternal diet can modulate the risk for cranial and neural tube defects. This article reviews recent progress toward a better understanding of nutrients during pregnancy, with particular focus on mouse models for defective neural tube closure. At least four major patterns of nutrient responses are apparent, suggesting that multiple pathways are involved in the response, and likely in the underlying pathogenesis of the defects. Folic acid has been the most widely studied nutrient, and the diverse responses of the mouse models to folic acid supplementation indicate that folic acid is not universally beneficial, but that the effect is dependent on genetic configuration. If this is the case for other nutrients as well, efforts to prevent neural tube defects with nutritional supplementation may need to become more specifically targeted than previously appreciated. Mouse models are indispensable for a better understanding of nutrient-gene interactions in normal pregnancies, as well as in those affected by metabolic diseases, such as diabetes and obesity.
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18
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Safra N, Bassuk AG, Ferguson PJ, Aguilar M, Coulson RL, Thomas N, Hitchens PL, Dickinson PJ, Vernau KM, Wolf ZT, Bannasch DL. Genome-wide association mapping in dogs enables identification of the homeobox gene, NKX2-8, as a genetic component of neural tube defects in humans. PLoS Genet 2013; 9:e1003646. [PMID: 23874236 PMCID: PMC3715436 DOI: 10.1371/journal.pgen.1003646] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 06/01/2013] [Indexed: 12/19/2022] Open
Abstract
Neural tube defects (NTDs) is a general term for central nervous system malformations secondary to a failure of closure or development of the neural tube. The resulting pathologies may involve the brain, spinal cord and/or vertebral column, in addition to associated structures such as soft tissue or skin. The condition is reported among the more common birth defects in humans, leading to significant infant morbidity and mortality. The etiology remains poorly understood but genetic, nutritional, environmental factors, or a combination of these, are known to play a role in the development of NTDs. The variable conditions associated with NTDs occur naturally in dogs, and have been previously reported in the Weimaraner breed. Taking advantage of the strong linkage-disequilibrium within dog breeds we performed genome-wide association analysis and mapped a genomic region for spinal dysraphism, a presumed NTD, using 4 affected and 96 unaffected Weimaraners. The associated region on canine chromosome 8 (pgenome =3.0 × 10(-5)), after 100,000 permutations, encodes 18 genes, including NKX2-8, a homeobox gene which is expressed in the developing neural tube. Sequencing NKX2-8 in affected Weimaraners revealed a G to AA frameshift mutation within exon 2 of the gene, resulting in a premature stop codon that is predicted to produce a truncated protein. The exons of NKX2-8 were sequenced in human patients with spina bifida and rare variants (rs61755040 and rs10135525) were found to be significantly over-represented (p=0.036). This is the first documentation of a potential role for NKX2-8 in the etiology of NTDs, made possible by investigating the molecular basis of naturally occurring mutations in dogs.
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Affiliation(s)
- Noa Safra
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California Davis, Davis, California, USA.
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Copp AJ, Stanier P, Greene NDE. Neural tube defects: recent advances, unsolved questions, and controversies. Lancet Neurol 2013; 12:799-810. [PMID: 23790957 DOI: 10.1016/s1474-4422(13)70110-8] [Citation(s) in RCA: 372] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Neural tube defects are severe congenital malformations affecting around one in every 1000 pregnancies. An innovation in clinical management has come from the finding that closure of open spina bifida lesions in utero can diminish neurological dysfunction in children. Primary prevention with folic acid has been enhanced through introduction of mandatory food fortification in some countries, although not yet in the UK. Genetic predisposition accounts for most of the risk of neural tube defects, and genes that regulate folate one-carbon metabolism and planar cell polarity have been strongly implicated. The sequence of human neural tube closure events remains controversial, but studies of mouse models of neural tube defects show that anencephaly, open spina bifida, and craniorachischisis result from failure of primary neurulation, whereas skin-covered spinal dysraphism results from defective secondary neurulation. Other malformations, such as encephalocele, are likely to be postneurulation disorders.
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Affiliation(s)
- Andrew J Copp
- Neural Development Unit and Newlife Birth Defects Research Centre, UCL Institute of Child Health, London, UK.
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20
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Wallingford JB, Niswander LA, Shaw GM, Finnell RH. The continuing challenge of understanding, preventing, and treating neural tube defects. Science 2013; 339:1222002. [PMID: 23449594 DOI: 10.1126/science.1222002] [Citation(s) in RCA: 306] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Human birth defects are a major public health burden: The Center for Disease Control estimates that 1 of every 33 United States newborns presents with a birth defect, and worldwide the estimate approaches 6% of all births. Among the most common and debilitating of human birth defects are those affecting the formation of the neural tube, the precursor to the central nervous system. Neural tube defects (NTDs) arise from a complex combination of genetic and environmental interactions. Although substantial advances have been made in the prevention and treatment of these malformations, NTDs remain a substantial public health problem, and we are only now beginning to understand their etiology. Here, we review the process of neural tube development and how defects in this process lead to NTDs, both in humans and in the animal models that serve to inform our understanding of these processes. The insights we are gaining will help generate new intervention strategies to tackle the clinical challenges and to alleviate the personal and societal burdens that accompany these defects.
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Affiliation(s)
- John B Wallingford
- Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA.
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21
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Spellicy CJ, Kosten TR, Hamon SC, Harding MJ, Nielsen DA. The MTHFR C677T Variant is Associated with Responsiveness to Disulfiram Treatment for Cocaine Dependency. Front Psychiatry 2013; 3:109. [PMID: 23335901 PMCID: PMC3544007 DOI: 10.3389/fpsyt.2012.00109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 12/01/2012] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVE Disulfiram is a one of the few pharmacotherapies for cocaine addiction that shows promise. Since disulfiram and cocaine both affect levels of global methylation we hypothesized the MTHFR gene, whose product is involved in supplying methyl groups for DNA and protein methylation, may be associated with responsiveness to disulfiram in cocaine-dependent individuals. METHODS Sixty-seven cocaine-dependent patients were stabilized on methadone for 2 weeks and then randomized into disulfiram (250 mg/day, N = 32) and placebo groups (N = 35) for 10 weeks. Patients were genotyped for the MTHFR (rs1801133, also known as C677T) polymorphism and the data was evaluated for association with cocaine-free urines in the disulfiram or placebo groups. Data from patients that completed all 10 weeks of the study (N = 56) were analyzed using repeated measures analysis of variance (ANOVA), corrected for population structure. RESULTS The CT or TT MTHFR genotype group (N = 32) dropped from 73 to 52% cocaine-positive urines on disulfiram (p = 0.0001), while the placebo group showed no treatment effect. The CC MTHFR genotype group (N = 24) showed a smaller, but still significant, reduction in cocaine-positive urines on disulfiram compared to placebo; 81-69% (p = 0.007). CONCLUSION This study indicates that a patient's MTHFR genotype may be used to identify individuals who might show improved response to disulfiram treatment for cocaine dependence. CLINICAL TRIAL Pharmacogenetics of Disulfiram for Cocaine, clinicaltrials.gov/ct2/show/NCT00149630, NIDA-18197-2, NCT00149630.
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Affiliation(s)
- Catherine J. Spellicy
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine and Michael E. DeBakey V. A. Medical CenterHouston, TX, USA
| | - Thomas R. Kosten
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine and Michael E. DeBakey V. A. Medical CenterHouston, TX, USA
| | - Sara C. Hamon
- Laboratory of Statistical Genetics, The Rockefeller UniversityNew York, NY, USA
| | - Mark J. Harding
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine and Michael E. DeBakey V. A. Medical CenterHouston, TX, USA
| | - David A. Nielsen
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine and Michael E. DeBakey V. A. Medical CenterHouston, TX, USA
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22
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Spellicy CJ, Northrup H, Fletcher JM, Cirino PT, Dennis M, Morrison AC, Martinez CA, Au KS. Folate metabolism gene 5,10-methylenetetrahydrofolate reductase (MTHFR) is associated with ADHD in myelomeningocele patients. PLoS One 2012; 7:e51330. [PMID: 23227261 PMCID: PMC3515551 DOI: 10.1371/journal.pone.0051330] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 11/07/2012] [Indexed: 02/06/2023] Open
Abstract
The objective of this study was to examine the relation between the 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene and behaviors related to attention- deficit/hyperactivity disorder (ADHD) in individuals with myelomeningocele. The rationale for the study was twofold: folate metabolizing genes, (e.g. MTHFR), are important not only in the etiology of neural tube defects but are also critical to cognitive function; and individuals with myelomeningocele have an elevated incidence of ADHD. Here, we tested 478 individuals with myelomeningocele for attention-deficit hyperactivity disorder behavior using the Swanson Nolan Achenbach Pelham-IV ADHD rating scale. Myelomeningocele participants in this group for whom DNAs were available were genotyped for seven single nucleotide polymorphisms (SNPs) in the MTHFR gene. The SNPs were evaluated for an association with manifestation of the ADHD phenotype in children with myelomeningocele. The data show that 28.7% of myelomeningocele participants exhibit rating scale elevations consistent with ADHD; of these 70.1% had scores consistent with the predominantly inattentive subtype. In addition, we also show a positive association between the SNP rs4846049 in the 3'-untranslated region of the MTHFR gene and the attention-deficit hyperactivity disorder phenotype in myelomeningocele participants. These results lend further support to the finding that behavior related to ADHD is more prevalent in patients with myelomeningocele than in the general population. These data also indicate the potential importance of the MTHFR gene in the etiology of the ADHD phenotype.
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Affiliation(s)
- Catherine J. Spellicy
- Department of Pediatrics, University of Texas Medical School at Houston, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Hope Northrup
- Department of Pediatrics, University of Texas Medical School at Houston, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Shriners Hospital for Children, Houston, Texas, United States of America
| | - Jack M. Fletcher
- Department of Psychology, University of Houston, Houston, Texas, United States of America
| | - Paul T. Cirino
- Department of Psychology and Texas Institute for Measurement, Evaluation, and Statistics (TIMES), University of Houston, Houston, Texas, United States of America
| | - Maureen Dennis
- Department of Surgery, University of Toronto, and Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Canada
| | - Alanna C. Morrison
- Human Genetics Center, Division of Epidemiology, Human Genetics and Environmental Science, School of Public Health, University of Texas Health Sciences Center at Houston, Houston, Texas, United States of America
| | - Carla A. Martinez
- Department of Obstetrics and Gynecology, Texas Tech University Health Science Center, El Paso, Texas, United States of America
| | - Kit Sing Au
- Department of Pediatrics, University of Texas Medical School at Houston, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
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Sullivan-Brown J, Goldstein B. Neural tube closure: the curious case of shrinking junctions. Curr Biol 2012; 22:R574-6. [PMID: 22835793 DOI: 10.1016/j.cub.2012.06.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Your brain and spinal cord began as a flat sheet, which narrowed, elongated, and rolled up to form a tube. A new study identifies a key molecular link underlying vertebrate neural tube formation, connecting planar cell polarity patterning to contraction of specific cell-cell junctions.
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Affiliation(s)
- Jessica Sullivan-Brown
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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24
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Juriloff DM, Harris MJ. Hypothesis: the female excess in cranial neural tube defects reflects an epigenetic drag of the inactivating X chromosome on the molecular mechanisms of neural fold elevation. ACTA ACUST UNITED AC 2012; 94:849-55. [PMID: 22753363 DOI: 10.1002/bdra.23036] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 04/04/2012] [Accepted: 05/01/2012] [Indexed: 01/10/2023]
Abstract
Females have long been known to be in excess among cranial neural tube defect (NTD) cases. Up to two thirds of human anencephalics and mouse exencephalics from various genetic causes are female, but the cause of this female excess is unknown. It appears not to be attributable to gonadal hormones, developmental delay in females, or preferential death of affected males. Recent studies of the Trp53 mouse mutant showed that exencephaly susceptibility depends on the presence of two X chromosomes, not the absence of the Y. Over a decade ago, we hypothesized that the relevant difference between female and male mammalian embryos at the time of cranial neural tube closure is the fact that females methylate most of the DNA in the large inactive X chromosome after every cell division, reducing the methylation available for other needs in female cells. Recently, the Whitelaw laboratory identified several proteins in mice (Momme D genes) involved in epigenetic silencing and methylation and shared in the silencing of transgenes, retrotransposons, and the inactive-X, and suggested that the inactive-X acts as a "sink" for epigenetic silencing proteins. The "inactive-X sink" hypothesis can be used to suggest expected changes in sex ratio in cranial NTDs in response to various genetic or environmental alterations. We recommend that observation of sex ratio become a standard component of all NTD studies. We suggest that the female excess among cranial NTDs is an epigenetic phenomenon whose molecular investigation will produce insight into the mechanisms underlying NTDs.
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Affiliation(s)
- Diana M Juriloff
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
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Narisawa A, Komatsuzaki S, Kikuchi A, Niihori T, Aoki Y, Fujiwara K, Tanemura M, Hata A, Suzuki Y, Relton CL, Grinham J, Leung KY, Partridge D, Robinson A, Stone V, Gustavsson P, Stanier P, Copp AJ, Greene ND, Tominaga T, Matsubara Y, Kure S. Mutations in genes encoding the glycine cleavage system predispose to neural tube defects in mice and humans. Hum Mol Genet 2012; 21:1496-503. [PMID: 22171071 PMCID: PMC3298276 DOI: 10.1093/hmg/ddr585] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 11/25/2011] [Accepted: 12/06/2011] [Indexed: 01/07/2023] Open
Abstract
Neural tube defects (NTDs), including spina bifida and anencephaly, are common birth defects of the central nervous system. The complex multigenic causation of human NTDs, together with the large number of possible candidate genes, has hampered efforts to delineate their molecular basis. Function of folate one-carbon metabolism (FOCM) has been implicated as a key determinant of susceptibility to NTDs. The glycine cleavage system (GCS) is a multi-enzyme component of mitochondrial folate metabolism, and GCS-encoding genes therefore represent candidates for involvement in NTDs. To investigate this possibility, we sequenced the coding regions of the GCS genes: AMT, GCSH and GLDC in NTD patients and controls. Two unique non-synonymous changes were identified in the AMT gene that were absent from controls. We also identified a splice acceptor site mutation and five different non-synonymous variants in GLDC, which were found to significantly impair enzymatic activity and represent putative causative mutations. In order to functionally test the requirement for GCS activity in neural tube closure, we generated mice that lack GCS activity, through mutation of AMT. Homozygous Amt(-/-) mice developed NTDs at high frequency. Although these NTDs were not preventable by supplemental folic acid, there was a partial rescue by methionine. Overall, our findings suggest that loss-of-function mutations in GCS genes predispose to NTDs in mice and humans. These data highlight the importance of adequate function of mitochondrial folate metabolism in neural tube closure.
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Affiliation(s)
- Ayumi Narisawa
- Department of Medical Genetics
- Department of Neurosurgery and
| | | | - Atsuo Kikuchi
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | | | | | - Kazuko Fujiwara
- Institute for Enzyme Research, University of Tokushima, Tokushima, Japan
| | | | - Akira Hata
- Department of Public Health, Chiba University School of Medicine, Chiba, Japan
| | - Yoichi Suzuki
- Department of Public Health, Chiba University School of Medicine, Chiba, Japan
| | - Caroline L. Relton
- Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - James Grinham
- Institute of Child Health, University College London, London, UK and
| | - Kit-Yi Leung
- Institute of Child Health, University College London, London, UK and
| | - Darren Partridge
- Institute of Child Health, University College London, London, UK and
| | - Alexis Robinson
- Institute of Child Health, University College London, London, UK and
| | - Victoria Stone
- Institute of Child Health, University College London, London, UK and
| | - Peter Gustavsson
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - Philip Stanier
- Institute of Child Health, University College London, London, UK and
| | - Andrew J. Copp
- Institute of Child Health, University College London, London, UK and
| | | | | | | | - Shigeo Kure
- Department of Medical Genetics
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
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26
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Rogers SW, Tvrdik P, Capecchi MR, Gahring LC. Prenatal ablation of nicotinic receptor alpha7 cell lineages produces lumbosacral spina bifida the severity of which is modified by choline and nicotine exposure. Am J Med Genet A 2012; 158A:1135-44. [PMID: 22473653 PMCID: PMC3415211 DOI: 10.1002/ajmg.a.35372] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 02/26/2012] [Indexed: 12/29/2022]
Abstract
Lumbosacral spina bifida is a common debilitating birth defect whose multiple causes are poorly understood. Here, we provide the first genetic delineation of cholinergic nicotinic receptor alpha7 (Chrna7) expression and link the ablation of the Chrna7 cell lineage to this condition in the mouse. Using homologous recombination, an IRES-Cre bi-cistronic cassette was introduced into the 3′ noncoding region of Chrna7 (Chrna7:Cre) for identifying cell lineages expressing this gene. This lineage first appears at embryonic day E9.0 in rhombomeres 3 and 5 of the neural tube and extends to cell subsets in most tissues by E14.5. Ablation of the Chrna7:Cre cell lineage in embryos from crosses with conditionally expressed attenuated diphtheria toxin results in precise developmental defects including omphalocele (89%) and open spina bifida (SB; 80%). We hypothesized that like humans, this defect would be modified by environmental compounds not only folic acid or choline but also nicotine. Prenatal chronic oral nicotine administration substantially worsened the defect to often include the rostral neural tube. In contrast, supplementation of the maternal diet with 2% choline decreased SB prevalence to 38% and dramatically reduced the defect severity. Folic acid supplementation only trended towards a reduced SB frequency. The omphalocele was unaffected by these interventions. These studies identify the Chrna7 cell lineage as participating in posterior neuropore closure and present a novel model of lower SB that can be substantially modified by the prenatal environment. © 2012 Wiley Periodicals, Inc.
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Affiliation(s)
- Scott W Rogers
- Salt Lake City VA Geriatric Research, Education and Clinical Center, Salt Lake City, Utah, USA.
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27
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Marini NJ, Hoffmann TJ, Lammer EJ, Hardin J, Lazaruk K, Stein JB, Gilbert DA, Wright C, Lipzen A, Pennacchio LA, Carmichael SL, Witte JS, Shaw GM, Rine J. A genetic signature of spina bifida risk from pathway-informed comprehensive gene-variant analysis. PLoS One 2011; 6:e28408. [PMID: 22140583 PMCID: PMC3227667 DOI: 10.1371/journal.pone.0028408] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 11/07/2011] [Indexed: 12/16/2022] Open
Abstract
Despite compelling epidemiological evidence that folic acid supplements reduce the frequency of neural tube defects (NTDs) in newborns, common variant association studies with folate metabolism genes have failed to explain the majority of NTD risk. The contribution of rare alleles as well as genetic interactions within the folate pathway have not been extensively studied in the context of NTDs. Thus, we sequenced the exons in 31 folate-related genes in a 480-member NTD case-control population to identify the full spectrum of allelic variation and determine whether rare alleles or obvious genetic interactions within this pathway affect NTD risk. We constructed a pathway model, predetermined independent of the data, which grouped genes into coherent sets reflecting the distinct metabolic compartments in the folate/one-carbon pathway (purine synthesis, pyrimidine synthesis, and homocysteine recycling to methionine). By integrating multiple variants based on these groupings, we uncovered two provocative, complex genetic risk signatures. Interestingly, these signatures differed by race/ethnicity: a Hispanic risk profile pointed to alterations in purine biosynthesis, whereas that in non-Hispanic whites implicated homocysteine metabolism. In contrast, parallel analyses that focused on individual alleles, or individual genes, as the units by which to assign risk revealed no compelling associations. These results suggest that the ability to layer pathway relationships onto clinical variant data can be uniquely informative for identifying genetic risk as well as for generating mechanistic hypotheses. Furthermore, the identification of ethnic-specific risk signatures for spina bifida resonated with epidemiological data suggesting that the underlying pathogenesis may differ between Hispanic and non-Hispanic groups.
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Affiliation(s)
- Nicholas J. Marini
- Department of Molecular and Cellular Biology, California Institute for Quantitative Biosciences, University of California, Berkeley, California, United States of America
- * E-mail: (NJM); (JR)
| | - Thomas J. Hoffmann
- Department of Epidemiology and Biostatistics and Institute of Human Genetics, University of California San Francisco, San Francisco, California, United States of America
| | - Edward J. Lammer
- Children's Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Jill Hardin
- VitaPath Genetics, Inc., Foster City, California, United States of America
| | - Katherine Lazaruk
- VitaPath Genetics, Inc., Foster City, California, United States of America
| | - Jason B. Stein
- VitaPath Genetics, Inc., Foster City, California, United States of America
| | - Dennis A. Gilbert
- VitaPath Genetics, Inc., Foster City, California, United States of America
| | - Crystal Wright
- Department of Energy, Joint Genome Institute, Walnut Creek, California, United States of America
| | - Anna Lipzen
- Department of Energy, Joint Genome Institute, Walnut Creek, California, United States of America
| | - Len A. Pennacchio
- Department of Energy, Joint Genome Institute, Walnut Creek, California, United States of America
| | - Suzan L. Carmichael
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| | - John S. Witte
- Department of Epidemiology and Biostatistics and Institute of Human Genetics, University of California San Francisco, San Francisco, California, United States of America
| | - Gary M. Shaw
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Jasper Rine
- Department of Molecular and Cellular Biology, California Institute for Quantitative Biosciences, University of California, Berkeley, California, United States of America
- * E-mail: (NJM); (JR)
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Marean A, Graf A, Zhang Y, Niswander L. Folic acid supplementation can adversely affect murine neural tube closure and embryonic survival. Hum Mol Genet 2011; 20:3678-83. [PMID: 21693562 DOI: 10.1093/hmg/ddr289] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Neural tube defects (NTDs), a common birth defect in humans, result from the failure of the embryonic neural tube (NT) to close properly. NT closure is a complex, poorly understood morphogenetic process influenced by genes and environment. The most effective environmental influence in decreasing the risk for NTDs is folic acid (FA) fortification and supplementation, and these findings led to the recommendation of periconceptual FA intake and mandatory fortification of the US grain supply in 1998. To explore the relationship between genetics and responsiveness to FA supplementation, we used five mouse NTDs models-Zic2, Shroom3, Frem2, Grhl2 (Grainyhead-like 2) and L3P (Line3P)-and a long-term generational FA supplementation scheme. Contrary to expectations, we find that three genetic mutants respond adversely to FA supplementation with increased incidence of NTDs in homozygous mutants, occurrence of NTDs in heterozygous embryos and embryonic lethality prior to NT closure. Because of these unexpected responses, we examined NTD risk after short-term FA supplementation. Our results indicate that, for the same genetic allele, NTD risk can depend on the length of FA exposure. Our data indicate that, depending on the gene mutation, FA supplementation may adversely influence embryonic development and NT closure.
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Affiliation(s)
- Amber Marean
- HHMI and Department of Pediatrics, Programs in Molecular Biology, University of Colorado AnschutzMedical Campus and Children’s Hospital Colorado, Aurora, CO 80045, USA
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29
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Ross ME. Gene-environment interactions, folate metabolism and the embryonic nervous system. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2010; 2:471-480. [PMID: 20836042 DOI: 10.1002/wsbm.72] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Formation of brain and spinal cord requires the successful closure of neural ectoderm into an embryonic neural tube. Defects in this process result in anencephaly or spina bifida, which together constitute a leading cause of mortality and morbidity in children, affecting all ethnic and socioeconomic groups. The subject of intensive research for decades, neural tube defects (NTDs), are understood to arise from complex interactions of genes and environmental conditions, though systems-level details are still elusive. Despite the variety of underlying causes, a single intervention, folic acid supplementation given in the first gestational month, can measurably reduce the occurrence of NTDs in a population. Evidence for and the scope of gene-environment interactions in the genesis of NTDs is discussed. A systems-based approach is now possible toward studies of genetic and environmental influences underlying NTDs that will enable the assessment of individual risk and personalized optimization of prevention.
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Affiliation(s)
- M Elizabeth Ross
- Laboratory of Neurogenetics & Development, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10065, USA
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Harris MJ, Juriloff DM. An update to the list of mouse mutants with neural tube closure defects and advances toward a complete genetic perspective of neural tube closure. ACTA ACUST UNITED AC 2010; 88:653-69. [PMID: 20740593 DOI: 10.1002/bdra.20676] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The number of mouse mutants and strains with neural tube defects (NTDs) now exceeds 240, including 205 representing specific genes, 30 for unidentified genes, and 9 multifactorial strains. These mutants identify genes needed for embryonic neural tube closure. Reports of 50 new NTD mutants since our 2007 review (Harris and Juriloff, 2007) were considered in relation to the previously reviewed mutants to obtain new insights into mechanisms of NTD etiology. In addition to null mutations, some are hypomorphs or conditional mutants. Some mutations do not cause NTDs on their own, but do so in digenic, trigenic, and oligogenic combinations, an etiology that likely parallels the nature of genetic etiology of human NTDs. Mutants that have only exencephaly are fourfold more frequent than those that have spina bifida aperta with or without exencephaly. Many diverse cellular functions and biochemical pathways are involved; the NTD mutants draw new attention to chromatin modification (epigenetics), the protease-activated receptor cascade, and the ciliopathies. Few mutants directly involve folate metabolism. Prevention of NTDs by maternal folate supplementation has been tested in 13 mutants and reduces NTD frequency in six diverse mutants. Inositol reduces spina bifida aperta frequency in the curly tail mutant, and three new mutants involve inositol metabolism. The many NTD mutants are the foundation for a future complete genetic understanding of the processes of neural fold elevation and fusion along mechanistically distinct cranial-caudal segments of the neural tube, and they point to several candidate processes for study in human NTD etiology.
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Affiliation(s)
- Muriel J Harris
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada.
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Werth M, Walentin K, Aue A, Schönheit J, Wuebken A, Pode-Shakked N, Vilianovitch L, Erdmann B, Dekel B, Bader M, Barasch J, Rosenbauer F, Luft FC, Schmidt-Ott KM. The transcription factor grainyhead-like 2 regulates the molecular composition of the epithelial apical junctional complex. Development 2010; 137:3835-45. [PMID: 20978075 DOI: 10.1242/dev.055483] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Differentiation of epithelial cells and morphogenesis of epithelial tubes or layers is closely linked with the establishment and remodeling of the apical junctional complex, which includes adherens junctions and tight junctions. Little is known about the transcriptional control of apical junctional complex components. Here, we show that the transcription factor grainyhead-like 2 (Grhl2), an epithelium-specific mammalian homolog of Drosophila Grainyhead, is essential for adequate expression of the adherens junction gene E-cadherin and the tight junction gene claudin 4 (Cldn4) in several types of epithelia, including gut endoderm, surface ectoderm and otic epithelium. We have generated Grhl2 mutant mice to demonstrate defective molecular composition of the apical junctional complex in these compartments that coincides with the occurrence of anterior and posterior neural tube defects. Mechanistically, we show that Grhl2 specifically associates with cis-regulatory elements localized at the Cldn4 core promoter and within intron 2 of the E-cadherin gene. Cldn4 promoter activity in epithelial cells is crucially dependent on the availability of Grhl2 and on the integrity of the Grhl2-associated cis-regulatory element. At the E-cadherin locus, the intronic Grhl2-associated cis-regulatory region contacts the promoter via chromatin looping, while loss of Grhl2 leads to a specific decrease of activating histone marks at the E-cadherin promoter. Together, our data provide evidence that Grhl2 acts as a target gene-associated transcriptional activator of apical junctional complex components and, thereby, crucially participates in epithelial differentiation.
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Affiliation(s)
- Max Werth
- Max-Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
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32
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Lu W, Guzman AR, Yang W, Chapa CJ, Shaw GM, Greene RM, Pisano MM, Lammer EJ, Finnell RH, Zhu H. Genes encoding critical transcriptional activators for murine neural tube development and human spina bifida: a case-control study. BMC MEDICAL GENETICS 2010; 11:141. [PMID: 20932315 PMCID: PMC2964532 DOI: 10.1186/1471-2350-11-141] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 10/08/2010] [Indexed: 11/11/2022]
Abstract
Background Spina bifida is a malformation of the neural tube and is the most common of neural tube defects (NTDs). The etiology of spina bifida is largely unknown, although it is thought to be multi-factorial, involving multiple interacting genes and environmental factors. Mutations in transcriptional co-activator genes-Cited2, p300, Cbp, Tfap2α, Carm1 and Cart1 result in NTDs in murine models, thus prompt us to investigate whether homologues of these genes are associated with NTDs in humans. Methods Data and biological samples from 297 spina bifida cases and 300 controls were derived from a population-based case-control study conducted in California. 37 SNPs within CITED2, EP300, CREBBP, TFAP2A, CARM1 and ALX1 were genotyped using an ABI SNPlex assay. Odds ratios and 95% confidence intervals were calculated for alleles, genotypes and haplotypes to evaluate the risk for spina bifida. Results Several SNPs showed increased or decreased risk, including CITED2 rs1131431 (OR = 5.32, 1.04~27.30), EP300 rs4820428 (OR = 1.30, 1.01~1.67), EP300 rs4820429 (OR = 0.50, 0.26~0.50, in whites, OR = 0.7, 0.49~0.99 in all subjects), EP300 rs17002284 (OR = 0.43, 0.22~0.84), TFAP2A rs3798691 (OR = 1.78, 1.13~2.87 in Hispanics), CREBBP rs129986 (OR = 0.27, 0.11~0.69), CARM1 rs17616105 (OR = 0.41, 0.22~0.72 in whites). In addition, one haplotype block in EP300 and one in TFAP2A appeared to be associated with increased risk. Conclusions Modest associations were observed in CITED2, EP300, CREBBP, TFAP2A and CARM1 but not ALX1. However, these modest associations were not statistically significant after correction for multiple comparisons. Searching for potential functional variants and rare causal mutations is warranted in these genes.
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Affiliation(s)
- Wei Lu
- Dell Pediatric Research Institute, UT Austin, Austin, TX, USA
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Au KS, Ashley-Koch A, Northrup H. Epidemiologic and genetic aspects of spina bifida and other neural tube defects. ACTA ACUST UNITED AC 2010; 16:6-15. [PMID: 20419766 DOI: 10.1002/ddrr.93] [Citation(s) in RCA: 187] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The worldwide incidence of neural tube defects (NTDs) ranges from 1.0 to 10.0 per 1,000 births with almost equal frequencies between two major categories: anencephaly and spina bifida (SB). Epidemiological studies have provided valuable insight for (a) researchers to identify nongenetic and genetic factors contributing to etiology, (b) public health officials to design and implement policies to prevent NTD pregnancies, and (c) individuals to take precautions to reduce the chance of having an NTD-affected pregnancy. Despite extensive research, our knowledge of the genetic etiology of human NTDs is limited. Although more than 200 small animal models with NTDs exist, most of these models do not replicate the human disease phenotype. Over a hundred candidate genes have been examined for risk association to human SB. The candidate genes studied include those important in folic acid metabolism, glucose metabolism, retinoid metabolism, and apoptosis. Many genes that regulate transcription in early embryogenesis and maintain planar cell polarity have also been tested as candidates. Additionally, genes identified through mouse models of NTDs have been explored as candidates. We do not know how many genes in the human genome may confer risk for NTDs in human. Less than 20% of the studied candidate genes have been determined to confer even a minor effect on risk association. Many studies have provided conflicting conclusions due to limitations in study design that potentially affect the power of statistical analysis. Future directions such as genomewide association studies (GWAS) and whole exome or even whole genome sequencing are discussed as possible avenues to identify genes that affect risk for human NTDs.
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Affiliation(s)
- Kit Sing Au
- Division of Medical Genetics, Department of Pediatrics, The University of Texas, Medical School at Houston, Houston, Texas 77030, USA
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De Castro SCP, Leung KY, Savery D, Burren K, Rozen R, Copp AJ, Greene ND. Neural tube defects induced by folate deficiency in mutant curly tail (Grhl3) embryos are associated with alteration in folate one-carbon metabolism but are unlikely to result from diminished methylation. BIRTH DEFECTS RESEARCH. PART A, CLINICAL AND MOLECULAR TERATOLOGY 2010; 88:612-8. [PMID: 20589880 PMCID: PMC3634156 DOI: 10.1002/bdra.20690] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Folate one-carbon metabolism has been implicated as a determinant of susceptibility to neural tube defects (NTDs), owing to the preventive effect of maternal folic acid supplementation and the higher risk associated with markers of diminished folate status. METHODS Folate one-carbon metabolism was compared in curly tail (ct/ct) and genetically matched congenic (+(ct)/+(ct)) mouse strains using the deoxyuridine suppression test in embryonic fibroblast cells and by quantifying s-adenosylmethionine (SAM) and s-adenosylhomocysteine (SAH) in embryos using liquid chromatography tandem mass spectrometry. A possible genetic interaction between curly tail and a null allele of 5,10-methylenetetrahydrofolate reductase (MTHFR) was investigated by generation of compound mutant embryos. RESULTS There was no deficit in thymidylate biosynthesis in ct/ct cells, but incorporation of exogenous thymidine was lower than in +(ct)/+(ct) cells. In +(ct)/+(ct) embryos the SAM/SAH ratio was diminished by dietary folate deficiency and normalized by folic acid or myo-inositol treatment, in association with prevention of NTDs. In contrast, folate deficiency caused a significant increase in the SAM/SAH ratio in ct/ct embryos. Loss of MTHFR function in curly tail embryos significantly reduced the SAM/SAH ratio but did not cause cranial NTDs or alter the frequency of caudal NTDs. CONCLUSIONS Curly tail fibroblasts and embryos, in which Grhl3 expression is reduced, display alterations in one-carbon metabolism, particularly in the response to folate deficiency, compared to genetically matched congenic controls in which Grhl3 is unaffected. However, unlike folate deficiency, diminished methylation potential appears to be insufficient to cause cranial NTDs in the curly tail strain, nor does it increase the frequency of caudal NTDs.
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Affiliation(s)
| | - Kit-yi Leung
- Neural Development Unit, UCL Institute of Child Health, London, UK
| | - Dawn Savery
- Neural Development Unit, UCL Institute of Child Health, London, UK
| | - Katie Burren
- Neural Development Unit, UCL Institute of Child Health, London, UK
| | | | - Andrew J. Copp
- Neural Development Unit, UCL Institute of Child Health, London, UK
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