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Aberrant neural tube morphology in Mthfd1l z/z embryos. ( A and J ) Mthfd1l z/ + embryos at approximately E10.5 and E11.5, respectively, exhibit re- gionalized β -galactosidase staining that is highest in the eyes, heart, limb, and dorsal midline region (black arrowheads). ( A ) Dashed line indicates the level of all sections below, at 10 × and 40 × magni fi cation. ( B and K ) Mthfd1l z/z littermates of embryos in ( A ) and ( J ), respectively, exhibit β -galactosidase staining that appears super fi cially ubiquitous. ( D, G, L, and N ) Sections through Mthfd1l z/ + embryos have β -galactosidase activity in the basal area of the dorsal neuro-
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Maternal supplementation with folic acid is known to reduce the incidence of neural tube defects (NTDs) by as much as 70%. Despite the strong clinical link between folate and NTDs, the biochemical mechanisms through which folic acid acts during neural tube development remain undefined. The Mthfd1l gene encodes a mitochondrial monofunctional 10-form...
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... of resorption. The most common NTD phenotype was exencephaly with a wavy neural tube ( Fig. 3D; n = 11), or exencephaly alone (Fig. 3B, n = 3). The most severe NTD observed was craniorachischisis ( Fig. 3C; n = 1). The nine Mthfd1l z/z embryos whose neural tubes had closed all displayed a wavy neural tube with a small, aberrantly formed head (Fig. 4B). In all, 20/24 Mthfd1l z/z embryos exhibited a wavy neural tube, and the earliest observation of this phenotype was at E9.5. The location of the waviness in the neural tube was variable, but most embryos exhibited a wavy neural tube begin- ning at approximately the same axis as the forelimb and extending caudally past the forelimb, as ...
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... (Fig. 2A). To confirm that the LacZ reporter recapitulated endogenous Mthfd1l gene expression, we compared the patterns detected by β-galactosidase staining in Mthfd1l z/+ sections with endogenous Mthfd1l gene expression. Using in situ hybridization, we observed transcript expression in the ectoderm, underlying mesenchyme, and dorsal neural tube (Fig. 4 C, F, and I). In the neural tube, the highest expression is detected in the basal surface of the dorsal neuroepithelium (Fig. 4F, arrowheads). β-galactosidase activity was more restricted in Mthfd1l z/+ embryos (Fig. 4D), but is still seen within the same region of the neural tube as the gene expression pattern. We conclude that the LacZ ...
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... by β-galactosidase staining in Mthfd1l z/+ sections with endogenous Mthfd1l gene expression. Using in situ hybridization, we observed transcript expression in the ectoderm, underlying mesenchyme, and dorsal neural tube (Fig. 4 C, F, and I). In the neural tube, the highest expression is detected in the basal surface of the dorsal neuroepithelium (Fig. 4F, arrowheads). β-galactosidase activity was more restricted in Mthfd1l z/+ embryos (Fig. 4D), but is still seen within the same region of the neural tube as the gene expression pattern. We conclude that the LacZ reporter partially recapitulates endoge- nous Mthfd1l gene expression with the difference most likely being due to reduced ...
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... Using in situ hybridization, we observed transcript expression in the ectoderm, underlying mesenchyme, and dorsal neural tube (Fig. 4 C, F, and I). In the neural tube, the highest expression is detected in the basal surface of the dorsal neuroepithelium (Fig. 4F, arrowheads). β-galactosidase activity was more restricted in Mthfd1l z/+ embryos (Fig. 4D), but is still seen within the same region of the neural tube as the gene expression pattern. We conclude that the LacZ reporter partially recapitulates endoge- nous Mthfd1l gene expression with the difference most likely being due to reduced ...
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... z/+ whole mount embryos stained for β-galactosidase activity have the highest levels in the eyes, heart, limb, and dorsal midline region (Fig. 4 A and J). In sectioned Mthfd1l z/+ embryos, β-galactosidase activity is predominantly detected at the basal surface of the dorsal neuroepithelium and is rarely detected in cells within and outside of the neural tube (Fig. 4 D, G, L, and N). In sectioned Mthfd1l z/z embryos, β-galactosidase activity is robustly detected both inside and outside ...
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... embryos stained for β-galactosidase activity have the highest levels in the eyes, heart, limb, and dorsal midline region (Fig. 4 A and J). In sectioned Mthfd1l z/+ embryos, β-galactosidase activity is predominantly detected at the basal surface of the dorsal neuroepithelium and is rarely detected in cells within and outside of the neural tube (Fig. 4 D, G, L, and N). In sectioned Mthfd1l z/z embryos, β-galactosidase activity is robustly detected both inside and outside the neural tube (Fig. 4 E, H, M, and O). Similar to Mthfd1l z/+ embryos, β-galactosidase is detected in the neuroepithelium; however, expression is less re- stricted dorsally in the nulls. In Mthfd1l z/z embryos with closed neural ...
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... sectioned Mthfd1l z/+ embryos, β-galactosidase activity is predominantly detected at the basal surface of the dorsal neuroepithelium and is rarely detected in cells within and outside of the neural tube (Fig. 4 D, G, L, and N). In sectioned Mthfd1l z/z embryos, β-galactosidase activity is robustly detected both inside and outside the neural tube (Fig. 4 E, H, M, and O). Similar to Mthfd1l z/+ embryos, β-galactosidase is detected in the neuroepithelium; however, expression is less re- stricted dorsally in the nulls. In Mthfd1l z/z embryos with closed neural tubes, the morphology was abnormal throughout the neural tube in all embryos sectioned (E10.5 and E11.5, n = 6). Neural tubes had ...
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... less re- stricted dorsally in the nulls. In Mthfd1l z/z embryos with closed neural tubes, the morphology was abnormal throughout the neural tube in all embryos sectioned (E10.5 and E11.5, n = 6). Neural tubes had abnormally shaped lumens, including asymmetric dor- sal-lateral bulges as well as a broader dorsal lumen that were not seen in controls (Fig. 4 D, E, G, H, and ...
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... can be rescued with maternal 5-formyl-THF sup- plementation (17). This rescue is "tunable," and depending on the dose of 5-formyl-THF administered to mothers during gestation, Folr1 −/− embryos develop NTDs and orofacial deformities or can be rescued to birth. Homozygous knockout of Shmt1, which encodes a cytoplasmic folate-metabolizing enzyme (Fig. 1, reaction 4), gives rise to a low frequency of NTDs in embryos from Shmt1 −/− dams fed a folate-deficient diet (18,19). Amt encodes an aminomethyltransferase that is a subunit of the mitochondrially localized glycine cleavage system (GCS), which processes glycine to donate 1C units to THF, forming CH 2 -THF (Fig. 1, reaction 5). Homozygous deletion ...
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... would cause a deficiency in cyto- plasmic 1C units, which are needed in stoichiometric amounts for purine and thymidylate production as well as the methyl cycle. The phenotypes of the Shmt1 and Amt knockout mice are consistent with this model of mammalian 1C metabolism. The Shmt1 gene, which encodes cytoplasmic serine hydroxymethyl- transferase (Fig. 1, cytoplasmic reaction 4), is not essential in mice (26), indicating that mitochondrial SHMT (mitochondrial reaction 4m) is fully capable of providing all of the 1C units needed in both the embryo and the adult. The neural tube phenotype in Amt nullizygous embryos lacking GCS activity (mitochondrial reaction 5) (20) is less severe than that in Mthfd1l knockout ...
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Background
Women in many countries are advised to use folic acid supplements before and early during pregnancy to reduce the risk of neural tube defects in their infants. This study aimed to update the prevalence and to identify possible determinants of preconception folic acid supplement use in Italian women.
Methods
The study was based on cross-...
Objective:
To examine changes in periconceptional folic acid supplementation behaviour among Chinese women of reproductive age after the implementation of a folic acid supplementation programme.
Design:
Two cross-sectional surveys were conducted.
Setting:
One survey was before (2002-2004) and the other was after (2011-2012) implementation of t...
![Fig. 4 Uptake of [ 14 C]-5-methyltetrahydrofolate in the renal BBMV as...](profile/Jyotdeep-Kaur/publication/259202397/figure/fig3/AS:601807948615683@1520493604539/Uptake-of-14-C-5-methyltetrahydrofolate-in-the-renal-BBMV-as-a-function-of-substrate_Q320.jpg)
Folic acid is the key one-carbon donor required for de novo nucleotide and methionine synthesis. Its deficiency is associated with megaloblastic anemia, cancer and various complications of pregnancy. However, its supplementation results in reduction of neural tube defects and prevention of several types of cancer. The intake of folic acid from fort...
Genetic variants in one-carbon folate metabolism have been identified as risk factors for disease because they may impair
the production or use of one-carbon folates required for nucleotide synthesis and methylation. p.R653Q (1958G>A) is a single-nucleotide
polymorphism (SNP) in the 10-formyltetrahydrofolate (formylTHF) synthetase domain of the tri...
Neural tube defects (NTDs) are common non-infectious congenital malformations resulting from improper neural tube closure. It is well established that periconceptional supplementation of folic acid reduces the occurrence and reoccurrence of NTDs, which led to mandatory folate fortification by many countries. In India even after huge efforts by gove...
Citations
... Some of these genes are evolutionarily highly conserved, and their role in neurulation has been shown in multiple vertebrate animal models [4]. Gene mutations have been identified as risk factors in the mouse model with NTDs, from which genes related to mitochondrial folate metabolism, such as MTHFD1L, AMT, SLC23A32, or the FOLR1 genes, are often incriminated [42][43][44][45][46][47][48][49][50]. Mutations in genes that control epigenetic activity, such as DNMT3B or abnormal epigenetic modification in LINE-1, JARID2, FBXL10, and SIRT1 genes, have been reported to have clinically seen consequences as NTDs [51][52][53]. ...
... Antiepileptic drugs (valproate, carbamazepine, phenobarbital) are associated with risk for NTDs, because their actions act as folate antagonists [35]. An important risk factor for NTDs is the deficiency in folic acid (vitamin B9), and laboratory animals with gene mutations in enzymes encoding mitochondrial folate metabolism express NTDs [45,46,48,49]. Folic acid in an essential nutrient for mammalian cell growth, being involved in the synthesis of essential components for fetal development, such as purine and pyrimidine, and in the conversion of homocysteine to methionine [62]. ...
Simple Summary
A stillborn male kitten from an accidental inbreeding was examined through different paraclinical methods, such as radiographic, CT, and cytohistological examination, due to the existence of severe neural tube defects associated with other congenital defects. The malformations observed included exencephaly–anencephaly, closed cranial spina bifida at the level of cervical vertebrae, maxillary brachygnathia, kyphoscoliosis, palatoschisis, and partial intestinal atresia. These severe malformations have a multifactorial cause in which both genetic and environmental factors can intervene. Inbreeding increases the possibilities of genetic defects to be expressed in the phenotype.
Abstract
Anencephaly, a severe neural tube defect characterized by the absence of major parts of the brain and skull, is a rare congenital disorder that has been observed in various species, including cats. Considering the uncommon appearance of anencephaly, this paper aims to present anencephaly in a stillborn male kitten from an accidental inbreeding using various paraclinical methods. Histological examination of tissue samples from the cranial region, where parts of the skull were absent, revealed the presence of atypical nerve tissue with neurons and glial cells organized in clusters, surrounded by an extracellular matrix and with an abundance of blood vessels, which are large, dilated, and filled with blood, not characteristic of nerve tissue structure. In CT scans, the caudal part of the frontal bone, the fronto-temporal limits, and the parietal bone were observed to be missing. CT also revealed that the dorsal tubercle of the atlas, the dorsal neural arch, and the spinal process of the C2–C7 bones were missing. In conclusion, the kitten was affected by multiple congenital malformations, a combination of exencephaly–anencephaly, maxillary brachygnathism, closed cranial spina bifida at the level of cervical vertebrae, kyphoscoliosis, palatoschisis, and partial intestinal atresia. The importance of employing imaging techniques cannot be overstated when it comes to the accurate diagnosis of neural tube defects.
... Supplementation with FA, a synthetic form of folate, is well known to cause a significant reduction in the risk of neural tube defects (NTD) [22]. In fact, strong evidence has been provided for a role for the mitochondrial folate pathway in neural tube development in an MTHFD1L-knockout mouse model, which presents NTD with 100% penetrance even when fed a folateproficient diet [23]. Several previous studies have also demonstrated the importance of folate in maintaining mitochondrial function [24]. ...
Background
Mitochondria have their own circular multi-copy genome (mtDNA), and abnormalities in the copy number are implicated in mitochondrial dysfunction, which contributes to a variety of aging-related pathologies. However, not much is known about the genetic correlation of mtDNA copy number across multiple generations and its physiological significance.
Methods
We measured the mtDNA copy number in cord blood or peripheral blood from 149 three-generation families, specifically the newborns, parents, and grandparents, of 149 families, totaling 1041 individuals. All of the biological specimens and information were provided by the Tohoku Medical Megabank Project in Japan. We also analyzed their maternal factors during pregnancy and neonatal outcomes.
Results
While the maternal peripheral blood mtDNA copy number was lower than that of other adult family members, it was negatively correlated with cord blood mtDNA copy number in male infants. Also, cord blood mtDNA copy numbers were negatively correlated with perinatal outcomes, such as gestation age, birth weight, and umbilical cord length, for both male and female neonates. Furthermore, the mtDNA copy number in the infants born to mothers who took folic acid supplements during pregnancy would be lower than in the infants born to mothers who did not take them.
Conclusions
This data-driven study offers the most comprehensive view to date on the genetic and physiological significance of mtDNA copy number in cord blood or peripheral blood taken from three generations, totaling more than 1000 individuals. Our findings indicate that mtDNA copy number would be one of the transgenerational biomarkers for assessing perinatal outcomes, as well as that appropriate medical interventions could improve the outcomes via quantitative changes in mtDNA.
... Multiple experimental systems have been developed to study the induction and rescue of NTDs during embryogenesis. Manipulation or mutation of specific genes like Pax3, components of the RA and Wnt/ PCP signaling pathways, folate metabolic enzymes, and other mutants (mostly in mice) have been used to study the formation of NTDs and their possible prevention (Zhang et al., 2007;Harris and Juriloff, 2010;Wen et al., 2010;Christensen et al., 2013;Momb et al., 2013;Zohn, 2020). In some of these experimental models, the NTDs can be rescued by FA supplementation, whereas others are resistant but can be rescued by other treatments such as inositol or RA (Greene and Copp, 2005;Harris and Juriloff, 2010;D'Souza et al., 2021;Li et al., 2018;Chen et al., 1994;Sudiwala et al., 2016). ...
Introduction: Neural tube defects (NTDs) are among the most debilitating and common developmental defects in humans. The induction of NTDs has been attributed to abnormal folic acid (vitamin B9) metabolism, Wnt and BMP signaling, excess retinoic acid (RA), dietary components, environmental factors, and many others. In the present study we show that reduced RA signaling, including alcohol exposure, induces NTDs.
Methods: Xenopus embryos were exposed to pharmacological RA biosynthesis inhibitors to study the induction of NTDs. Embryos were treated with DEAB, citral, or ethanol, all of which inhibit the biosynthesis of RA, or injected to overexpress Cyp26a1 to reduce RA. NTD induction was studied using neural plate and notochord markers together with morphological analysis. Expression of the neuroectodermal regulatory network and cell proliferation were analyzed to understand the morphological malformations of the neural plate.
Results: Reducing RA signaling levels using retinaldehyde dehydrogenase inhibitors (ethanol, DEAB, and citral) or Cyp26a1-driven degradation efficiently induce NTDs. These NTDs can be rescued by providing precursors of RA. We mapped this RA requirement to early gastrula stages during the induction of neural plate precursors. This reduced RA signaling results in abnormal expression of neural network genes, including the neural plate stem cell maintenance genes, geminin, and foxd4l1.1. This abnormal expression of neural network genes results in increased proliferation of neural precursors giving rise to an expanded neural plate.
Conclusion: We show that RA signaling is required for neural tube closure during embryogenesis. RA signaling plays a very early role in the regulation of proliferation and differentiation of the neural plate soon after the induction of neural progenitors during gastrulation. RA signaling disruption leads to the induction of NTDs through the mis regulation of the early neuroectodermal network, leading to increased proliferation resulting in the expansion of the neural plate. Ethanol exposure induces NTDs through this mechanism involving reduced RA levels.
... The neural tube is one of the tissues closest to the somite in the embryo. The MTHFD1L gene is involved in one-carbon folate metabolism and has been reported to be associated with a neural tube defect (Momb et al., 2013). The number of somites in MTHFD1L-knockout mouse embryos was significantly lower than that in normal mouse embryos at the same observed time points (Shin et al., 2019). ...
The number of ribs (NR) and carcass length (CL) are important economic traits in pig breeding programs. Pigs with a higher NR and longer CL produce greater pork yields. In the present study, Suhuai pigs with NR and CL phenotypes were genotyped using the Neogen® GGP Porcine 80 K SNP array to identify the QTL affecting NR and CL and dissect the candidate genes for the two traits. The SNP‐chip data was imputed to the whole‐genome sequence (iWGS) to increase the probability of identifying causal variants. Through genome‐wide association studies (GWAS) based on both chip and iWGS data, significant SNPs were detected on Sus scrofa chromosome (SSC) 1, SSC4 and SSC7 for NR and on SSC5, SSC16 and SSC17 for CL. Moreover, two SNPs (H3GA0022644 and WU_10.2_7_103460706) on SSC7 detected in chip‐based GWAS were significantly associated with both NR and CL. Through Bayes fine mapping, one reported QTL for NR on SSC7 and two reported QTL for CL on SSC17 were verified, and two new QTL (SSC1: 14.05–15.84 Mb and SSC4: 64.83–66.59 Mb) affecting NR and two new QTL (SSC5: 58.31–59.84 Mb and SSC16: 22.98–23.43 Mb) affecting CL were detected. According to the biological functions of genes, MTHFD1L on SSC1 and SULF1 on SSC4 are novel functional candidate genes for NR, and EMP1 on SSC5 and EGFLAM on SSC16 are novel functional candidate genes for CL. Overall, our findings provide a basis for identifying new causal genes and mutations affecting NR and CL.
... The here shown data also highlight that formate, in addition to its role as an anabolic substrate, can play a role as a signaling molecule in cellular plasticity. Such a fundamental function might also explain the observation that loss of MTHFD1L results in neural-tube defects during embryogenesis (Momb et al., 2013). ...
Metabolic rewiring is essential to enable cancer onset and progression. One important metabolic pathway that is often hijacked by cancer cells is the one-carbon cycle, in which the third carbon of serine is oxidized to formate. We have previously shown that formate production in cancer cells often exceeds the anabolic demand, resulting in formate overflow. Furthermore, we observed that high extracellular formate promotes the in vitro invasiveness of glioblastoma (GBM) cells. However, additional data supporting this in vitro observation and mechanistic details remained elusive so far.
In the present study, we now demonstrate that inhibition of formate overflow results in a decreased invasiveness of GBM cells ex vivo and in vivo. Additionally, we observed that exposure to exogeneous formate can induce a transiently stable pro-invasive phenotype that results in increased metastasis formation in vivo. All in all, these results suggest that a local formate increase within the tumor microenvironment may be one factor that can promote cancer cell motility and dissemination.
Mechanistically, we uncover a previously undescribed interplay where formate acts as a trigger to alter fatty acid metabolism and matrix metalloproteinase (MMP) activity which in turn impacts cancer cell invasiveness.
We thus highlight the role of formate as a pro-invasive metabolite. Gaining a deeper understanding of formate overflow and how it promotes invasion in cancer, may open new therapeutic opportunities to prevent cancer cell dissmination.
... El laboratorio de Appling descubrió el gen humano responsable de la producción de formiato en las mitocondrias (Momb et al., 2013). No tiene un nombre llamativo: metilentetrahidrofolato deshidrogenasa como 1. Lo llamaremos el gen productor de formiato de mitocondria. ...
... La misma causa de muerte de los embriones de ratón sin el gen productor de formiato de mitocondria. Sus tubos neurales no se cerraban correctamente (Momb et al., 2013). ...
La nutrición moderna es todo acerca de calorías, grasas, proteínas y carbohidratos. ¿Qué pasa con nuestro ADN? Para hacer ADN necesitamos los aminoácidos aspartato, glutamina y glicina. Eso está cubierto por la ingestión diaria de proteínas. Pero necesitamos un ingrediente más: el formiato. ¿Qué es el formiato? ¿De dónde viene? ¿Qué pasa si mi consumo de formiato es bajo? ¿Qué pasa si como demasiado formiato? Este libro proporciona la respuesta a estas preguntas.
... It further binds the autophagy receptor OPTN (optineurin), which enhances OPTN accumulation on depolarized mitochondria and aids mitophagy [90]. Moreover, several studies have also suggested that mtDNA mutations [91,92] and abnormalities in complex I of the mitochondrial ETC [93] play an essential role in the etiopathogenesis of PD. According to theories put forth by researchers [94], the substantia nigra-a group of dopaminergic neurons of the midbrain that undergoes age-related neurodegeneration in PD patients, has high oxidative capacities, and that seems to be particularly sensitive to mitochondrial dysfunction [95], loss in the respiratory chain and, subsequently, high oxidative stress-that is uniquely susceptible to the accumulation of somatic mtDNA mutations and deletions over time [96]. ...
Mitochondria are implicated in a wide range of functions apart from ATP generation, and, therefore, constitute one of the most important organelles of cell. Since healthy mitochondria are essential for proper cellular functioning and survival, mitochondrial dysfunction may lead to various pathologies. Mitochondria are considered a novel and promising therapeutic target for the diagnosis, treatment, and prevention of various human diseases including metabolic disorders, cancer, and neurodegenerative diseases. For mitochondria-targeted therapy, there is a need to develop an effective drug delivery approach, owing to the mitochondrial special bilayer structure through which therapeutic molecules undergo multiple difficulties in reaching the core. In recent years, various nanoformulations have been designed such as polymeric nanoparticles, liposomes, inorganic nanoparticles conjugate with mitochondriotropic moieties such as mitochondria-penetrating peptides (MPPs), triphenylphosphonium (TPP), dequalinium (DQA), and mitochondrial protein import machinery for overcoming barriers involved in targeting mitochondria. The current approaches used for mitochondria-targeted drug delivery have provided promising ways to overcome the challenges associated with targeted-drug delivery. Herein, we review the research from past years to the current scenario that has identified mitochondrial dysfunction as a major contributor to the pathophysiology of various diseases. Furthermore, we discuss the recent advancements in mitochondria-targeted drug delivery strategies for the pathologies associated with mitochondrial dysfunction.
... One carbon metabolism is critical for nervous system development and neural programming (32). Crucial another critical enzyme of one carbon metabolism within the mitochondria, is not only embryonically lethal but also leads to neural tube defects in mice (35). Thus, manipulation of one carbon metabolism could be a potential therapeutic approach to the pathology resulting from a loss of TMEM65 protein. ...
Depletion of transmembrane protein 65 (TMEM65) in a patient with a homozygous point mutation in the TMEM65 gene splice site was reported to result in mitochondrial dysfunction and severe encephalomyopathy(1), indicating the clinical importance of TMEM65. However, the function of TMEM65 remains unknown, and the specific subcellular localization of TMEM65 to either the mitochondrial inner membrane or cardiac intercalated disc remains controversial. Here, we generated a Tmem65 reporter mouse as well as whole-body and tissue-specific Tmem65 knockout (KO) mice to investigate the localization and function of TMEM65. We show that TMEM65 is localized to mitochondria in heart, skeletal muscle, and throughout the brain. Both whole-body and nervous system-specific Tmem65 KO resulted in severe growth retardation and sudden death following seizures ~3 weeks after birth indicating TMEM65 is indispensable for normal brain function. Cardiac-specific Tmem65 KO mice were viable and fertile but had reduced mitochondrial content and cardiac stress response. Skeletal muscle-specific Tmem65 KO led to progressive, adult-onset myopathy manifested by wasting of muscle fibers, upregulation of one-carbon metabolic pathways, and reduced whole-body metabolic efficiency. These results highlight the effectiveness of a Tmem65 KO mouse model to recapitulate and further interrogate the clinical phenotypes associated with a loss of TMEM65.
... The mechanisms by which the association between folate metabolism and AD can be explained are the following: 1. Folate is a cofactor in the metabolism of carbon, during which it promotes the remethylation of homocysteine, a cytotoxic amino acid that contains Sulfur that can induce DNA chain breakage and oxidative stress, promoting the generation of reactive oxygen species (ROS) and cell death by apoptosis [150][151][152] and 2. Elevated homocysteine contributes to the risk of AD by causing vascular alterations, which have been directly related to AD and can cause a cholinergic deficit in cortical neurons due to its toxicity [153]. This gene has also been associated with neural tube defects that include spina bifida, meningocele, encephalocele, and anencephaly, as a result of abnormalities in proliferation, differentiation, and death of neural cells [154][155][156]; and with adenocarcinoma and it has been considered as a new molecular target for cancer therapy [157][158][159][160]. The R564H variant found in the exome analysis was evaluated in the structural model that was built. ...
Alzheimer’s disease (AD) is the most common cause of dementia in the elderly, affecting over 50 million people worldwide in 2020 and this number will triple to 152 million by 2050. Much of the increase will be in developing countries like Colombia. In familial forms, highly penetrant mutations have been identified in three genes, APP, PSEN1, and PSEN2, supporting a role for amyloid-β peptide. In sporadic forms, more than 30 risk genes involved in the lipid metabolism, the immune system, and synaptic functioning mechanisms. We used whole-exome sequencing (WES) to evaluate a family of 97 members, spanning three generations, with a familiar AD, and without mutations in APP, PSEN1, or PSEN2. We sequenced two affected and one unaffected member with the aim of identifying genetic variants that could explain the presence of the disease in the family and the candidate variants were validated in eleven members. We also built a structural model to try to determine the effect on protein function. WES analysis identified two rare variants in SORL1 and MTHFD1L genes segregating in the family with other potential risk variants in APOE, ABCA7, and CHAT, suggesting an oligogenic inheritance. Additionally, the structural 3D models of SORL1 and MTHFD1L variants shows that these variants produce polarity changes that favor hydrophobic interactions, resulting in local structural changes that could affect the protein function and may contribute to the development of the disease in this family.
... Folate is an essential vitamin for vertebrates which is taken up by cells through the reduced folate carrier (RFC1, also known as SLC19A1) and the folate receptor alpha FOLR1 (Ratnam et al., 1989;Kur et al., 2014). Both folate deficiency and mutations in genes involved in the folate pathway cause several developmental defects including neural tube and neural crest-related defects in the vertebrate models and humans (Burgoon et al., 2002;Tang et al., 2005;Wilcox et al., 2007;Wehby and Murray, 2010;Li et al., 2011;Lee et al., 2012;Kao et al., 2013;Momb et al., 2013). Inside the cell, folate is required for one-carbon metabolism to transmit methyl groups for the production of S-adenosylmethionine (SAM). ...
... Folate deficiency alters neural crest specification, migration, and even differentiation (Burgoon et al., 2002;Tang et al., 2005; Momb et al., 2013;Wahl et al., 2015;Alata Jimenez et al., 2018). However, the role of folate and DNA methylation during NP and NPB segregation is unclear. ...
The neural plate border (NPB) of vertebrate embryos segregates from the neural and epidermal regions, and it is comprised of an intermingled group of multipotent progenitor cells. Folate is the precursor of S-adenosylmethionine, the main methyl donor for DNA methylation, and it is critical for embryonic development, including the specification of progenitors which reside in the NPB. Despite the fact that several intersecting signals involved in the specification and territorial restriction of NPB cells are known, the role of epigenetics, particularly DNA methylation, has been a matter of debate. Here, we examined the temporal and spatial distribution of the methyl source and analyzed the abundance of 5mC/5 hmC and their epigenetic writers throughout the segregation of the neural and NPB territories. Reduced representation bisulfite sequencing (RRBS) on Reduced Folate Carrier 1 (RFC1)-deficient embryos leads to the identification of differentially methylated regions (DMRs). In the RFC1-deficient embryos, we identified several DMRs in the Notch1 locus, and the spatiotemporal expression of Notch1 and its downstream target gene Bmp4 were expanded in the NPB. Cell fate analysis on folate deficient embryos revealed a significant increase in the number of cells coexpressing both neural (SOX2) and NPB (PAX7) markers, which may represent an enhancing effect in the cellular potential of those progenitors. Taken together, our findings propose a model where the RFC1 deficiency drives methylation changes in specific genomic regions that are correlated with a dysregulation of pathways involved in early development such as Notch1 and BMP4 signaling. These changes affect the potency of the progenitors residing in the juncture of the neural plate and NPB territories, thus driving them to a primed state.
