RESUMEN
Prescriptions for antiseizure medications (ASMs) have been rapidly growing over the last several decades due, in part, to an expanding list of clinical indications for which they are now prescribed. This trend has raised concern for potential adverse neurodevelopmental outcomes in ASM-exposed pregnancies. Recent large scale population studies have suggested that the use of topiramate (TOPAMAX, Janssen-Cilag), when prescribed for seizure control, migraines, and/or weight management, is associated with an increased risk for autism spectrum disorder (ASD), intellectual disability, and attention-deficit/hyperactivity disorder (ADHD) in exposed offspring. Here, we critically review epidemiologic evidence demonstrating the neurobehavioral teratogenicity of topiramate and speculate on the neuromolecular mechanisms by which prenatal exposure may perturb neurocognitive development. Specifically, we explore the potential role of topiramate's pharmacological interactions with ligand- and voltage-gated ion channels, especially GABAergic signaling, its effects on DNA methylation and histone acetylation, whether topiramate induces oxidative stress, and its association with fetal growth restriction as possible mechanisms contributing to neurodevelopmental toxicity. Resolving this biology will be necessary to reduce the risk of adverse pregnancy outcomes caused by topiramate or other ASMs.
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Anticonvulsivantes , Topiramato , Topiramato/toxicidad , Humanos , Embarazo , Anticonvulsivantes/toxicidad , Femenino , Efectos Tardíos de la Exposición Prenatal , Trastornos del Neurodesarrollo/inducido químicamente , Animales , Fructosa/análogos & derivados , Fructosa/toxicidadRESUMEN
Background: Mesenchymal stem cells (MSCs) from gestational tissues represent promising strategies for in utero treatment of congenital malformations, but plasticity and required high-risk surgical procedures limit their use. Here we propose natural exosomes (EXOs) isolated from amniotic fluid-MSCs (AF-MSCs), and their mimetic counterparts (MIMs), as valid, stable, and minimally invasive therapeutic alternatives. Methods: MIMs were generated from AF-MSCs by combining sequential filtration steps through filter membranes with different porosity and size exclusion chromatography columns. Physiochemical and molecular characterization was performed to compare them to EXOs released from the same number of cells. The possibility to exploit both formulations as mRNA-therapeutics was explored by evaluating cell uptake (using two different cell types, fibroblasts, and macrophages) and mRNA functionality overtime in an in vitro experimental setting as well as in an ex vivo, whole embryo culture using pregnant C57BL6 dams. Results: Molecular and physiochemical characterization showed no differences between EXOs and MIMs, with MIMs determining a 3-fold greater yield. MIMs delivered a more intense and prolonged expression of mRNA encoding for green fluorescent protein (GFP) in macrophages and fibroblasts. An ex-vivo whole embryo culture demonstrated that MIMs mainly accumulate at the level of the yolk sac, while EXOs reach the embryo. Conclusions: The present data confirms the potential application of EXOs for the prenatal repair of neural tube defects and proposes MIMs as prospective vehicles to prevent congenital malformations caused by in utero exposure to drugs.
RESUMEN
Neurulation is a highly synchronized biomechanical process leading to the formation of the brain and spinal cord, and its failure leads to neural tube defects (NTDs). Although we are rapidly learning the genetic mechanisms underlying NTDs, the biomechanical aspects are largely unknown. To understand the correlation between NTDs and tissue stiffness during neural tube closure (NTC), we imaged an NTD murine model using optical coherence tomography (OCT), Brillouin microscopy and confocal fluorescence microscopy. Here, we associate structural information from OCT with local stiffness from the Brillouin signal of embryos undergoing neurulation. The stiffness of neuroepithelial tissues in Mthfd1l null embryos was significantly lower than that of wild-type embryos. Additionally, exogenous formate supplementation improved tissue stiffness and gross embryonic morphology in nullizygous and heterozygous embryos. Our results demonstrate the significance of proper tissue stiffness in normal NTC and pave the way for future studies on the mechanobiology of normal and abnormal embryonic development.
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Tubo Neural , Neurulación , Tomografía de Coherencia Óptica , Animales , Femenino , Ratones , Fenómenos Biomecánicos , Embrión de Mamíferos/metabolismo , Formiato-Tetrahidrofolato Ligasa/genética , Formiato-Tetrahidrofolato Ligasa/metabolismo , Formiatos/metabolismo , Metilenotetrahidrofolato Deshidrogenasa (NADP)/genética , Metilenotetrahidrofolato Deshidrogenasa (NADP)/metabolismo , Ratones Noqueados , Microscopía Confocal , Mutación/genética , Tubo Neural/metabolismo , Defectos del Tubo Neural/genética , Defectos del Tubo Neural/metabolismo , Defectos del Tubo Neural/patología , Neurulación/genética , Tomografía de Coherencia Óptica/métodosRESUMEN
Valproic acid (VPA, valproate, Depakote) is a commonly used anti-seizure medication (ASM) in the treatment of epilepsy and a variety of other neurological disorders. While VPA and other ASMs are efficacious for management of seizures, they also increase the risk for adverse pregnancy outcomes, including neural tube defects (NTDs). Thus, the utility of these drugs during pregnancy and in women of childbearing potential presents a continuing public health challenge. Elucidating the underlying genetic or metabolic risk factors for VPA-affected pregnancies may lead to development of non-teratogenic ASMs, novel prevention strategies, or more targeted methods for managing epileptic pregnancies. To address this challenge, we performed unbiased, whole embryo metabolomic screening of E8.5 mouse embryos from two inbred strains with differential susceptibility to VPA-induced NTDs. We identified metabolites of differential abundance between the two strains, both in response to VPA exposure and in the vehicle controls. Notable enriched pathways included lipid metabolism, carnitine metabolism, and several amino acid pathways, especially cysteine and methionine metabolism. There also was increased abundance of ω-oxidation products of VPA in the more NTD-sensitive strain, suggesting differential metabolism of the drug. Finally, we found significantly reduced levels of hypotaurine in the susceptible strain regardless of VPA status. Based on this information, we hypothesized that maternal supplementation with L-carnitine (400 mg/kg), coenzyme A (200 mg/kg), or hypotaurine (350 mg/kg) would reduce VPA-induced NTDs in the sensitive strain and found that administration of hypotaurine prior to VPA exposure significantly reduced the occurrence of NTDs by close to one-third compared to controls. L-carnitine and coenzyme A reduced resorption rates but did not significantly reduce NTD risk in the sensitive strain. These results suggest that genetic variants or environmental exposures influencing embryonic hypotaurine status may be factors in determining risk for adverse pregnancy outcomes when managing the health care needs of pregnant women exposed to VPA or other ASMs.
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Neural tube defects (NTDs) are a group of common and severe congenital malformations. The PI3K-AKT signalling pathway plays a crucial role in the neural tube development. There is limited evidence concerning any possible association between aberrant methylation in PI3K-AKT signalling pathway genes and NTDs. Therefore, we aimed to investigate potential associations between aberrant methylation of PI3K-AKT pathway genes and NTDs. Methylation studies of PI3K-AKT pathway genes utilizing microarray genome-methylation data derived from neural tissues of ten NTD cases and eight non-malformed controls were performed. Targeted DNA methylation analysis was subsequently performed in an independent cohort of 73 NTD cases and 32 controls to validate the methylation levels of identified genes. siRNAs were used to pull-down the target genes in human embryonic stem cells (hESCs) to examine the effects of the aberrant expression of target genes on neural cells. As a result, 321 differentially hypermethylated CpG sites in the promoter regions of 30 PI3K-AKT pathway genes were identified in the microarray data. In target methylation analysis, CHRM1, FGF19, and ITGA7 were confirmed to be significantly hypermethylated in NTD cases and were associated with increased risk for NTDs. The down-regulation of FGF19, CHRM1, and ITGA7 impaired the formation of rosette-like cell aggregates. The down-regulation of those three genes affected the expression of PAX6, SOX2 and MAP2, implying their influence on the differentiation of neural cells. This study for the first time reported that hypermethylation of PI3K-AKT pathway genes such as CHRM1, FGF19, and ITGA7 is associated with human NTDs.
Asunto(s)
Defectos del Tubo Neural , Proteínas Proto-Oncogénicas c-akt , Antígenos CD/genética , Antígenos CD/metabolismo , Metilación de ADN , Factores de Crecimiento de Fibroblastos/genética , Factores de Crecimiento de Fibroblastos/metabolismo , Humanos , Cadenas alfa de Integrinas/genética , Cadenas alfa de Integrinas/metabolismo , Defectos del Tubo Neural/genética , Defectos del Tubo Neural/metabolismo , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptor Muscarínico M1/genética , Receptor Muscarínico M1/metabolismo , Transducción de SeñalRESUMEN
Neural tube defects (NTDs) are a classic example of preventable birth defects for which there is a proven-effective intervention, folic acid (FA); however, further methods of prevention remain unrealized. In the decades following implementation of FA nutritional fortification programs throughout at least 87 nations, it has become apparent that not all NTDs can be prevented by FA. In the United States, FA fortification only reduced NTD rates by 28-35% (Williams et al., 2015). As such, it is imperative that further work is performed to understand the risk factors associated with NTDs and their underlying mechanisms so that alternative prevention strategies can be developed. However, this is complicated by the sheer number of genes associated with neural tube development, the heterogeneity of observable phenotypes in human cases, the rareness of the disease, and the myriad of environmental factors associated with NTD risk. Given the complex genetic architecture underlying NTD pathology and the way in which that architecture interacts dynamically with environmental factors, further prevention initiatives will undoubtedly require precision medicine strategies that utilize the power of human genomics and modern tools for assessing genetic risk factors. Herein, we review recent advances in genomic strategies for discovering genetic variants associated with these defects, and new ways in which biological models, such as mice and cell culture-derived organoids, are leveraged to assess mechanistic functionality, the way these variants interact with other genetic or environmental factors, and their ultimate contribution to human NTD risk.
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Genómica/métodos , Defectos del Tubo Neural/genética , Animales , Modelos Animales de Enfermedad , Predisposición Genética a la Enfermedad , Humanos , Mutación , Defectos del Tubo Neural/metabolismoRESUMEN
Here we describe the development and characterization of the photo-N-degron, a peptide tag that can be used in optogenetic studies of protein function in vivo. The photo-N-degron can be expressed as a genetic fusion to the amino termini of other proteins, where it undergoes a blue light-dependent conformational change that exposes a signal for the class of ubiquitin ligases, the N-recognins, which mediate the N-end rule mechanism of proteasomal degradation. We demonstrate that the photo-N-degron can be used to direct light-mediated degradation of proteins in Saccharomyces cerevisiae and Drosophila melanogaster with fine temporal control. In addition, we compare the effectiveness of the photo-N-degron with that of two other light-dependent degrons that have been developed in their abilities to mediate the loss of function of Cactus, a component of the dorsal-ventral patterning system in the Drosophila embryo. We find that like the photo-N-degron, the blue light-inducible degradation (B-LID) domain, a light-activated degron that must be placed at the carboxy terminus of targeted proteins, is also effective in eliciting light-dependent loss of Cactus function, as determined by embryonic dorsal-ventral patterning phenotypes. In contrast, another previously described photosensitive degron (psd), which also must be located at the carboxy terminus of associated proteins, has little effect on Cactus-dependent phenotypes in response to illumination of developing embryos. These and other observations indicate that care must be taken in the selection and application of light-dependent and other inducible degrons for use in studies of protein function in vivo, but importantly demonstrate that N- and C-terminal fusions to the photo-N-degron and the B-LID domain, respectively, support light-dependent degradation in vivo.
Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Drosophila melanogaster/efectos de la radiación , Optogenética/métodos , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/efectos de la radiación , Animales , Arginina/metabolismo , Avena , Núcleo Celular/metabolismo , Núcleo Celular/efectos de la radiación , Oscuridad , Drosophila melanogaster/embriología , Embrión no Mamífero/metabolismo , Embrión no Mamífero/efectos de la radiación , Femenino , Fluorescencia , Rayos Láser , Luz , Mutación con Pérdida de Función , Masculino , Proteínas de Neoplasias/metabolismo , Fenotipo , Complejo de la Endopetidasa Proteasomal/metabolismo , Dominios Proteicos/efectos de la radiación , Proteínas Serina-Treonina Quinasas/química , Proteolisis/efectos de la radiación , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
Background Cerebral folate deficiency (CFD) syndrome is characterised by a low concentration of 5-methyltetrahydrofolate in cerebrospinal fluid, while folate levels in plasma and red blood cells are in the low normal range. Mutations in several folate pathway genes, including FOLR1 (folate receptor alpha, FRα), DHFR (dihydrofolate reductase) and PCFT (proton coupled folate transporter) have been previously identified in patients with CFD. Methods In an effort to identify causal mutations for CFD, we performed whole exome sequencing analysis on eight CFD trios and identified eight de novo mutations in seven trios. Results Notably, we found a de novo stop gain mutation in the capicua (CIC) gene. Using 48 sporadic CFD samples as a validation cohort, we identified three additional rare variants in CIC that are putatively deleterious mutations. Functional analysis indicates that CIC binds to an octameric sequence in the promoter regions of folate transport genes: FOLR1, PCFT and reduced folate carrier (Slc19A1; RFC1). The CIC nonsense variant (p.R353X) downregulated FOLR1 expression in HeLa cells as well as in the induced pluripotent stem cell (iPSCs) derived from the original CFD proband. Folate binding assay demonstrated that the p.R353X variant decreased cellular binding of folic acid in cells. Conclusion This study indicates that CIC loss of function variants can contribute to the genetic aetiology of CFD through regulating FOLR1 expression. Our study described the first mutations in a non-folate pathway gene that can contribute to the aetiology of CFD.
Asunto(s)
Cerebro/metabolismo , Receptor 1 de Folato/genética , Deficiencia de Ácido Fólico/líquido cefalorraquídeo , Mutación con Pérdida de Función , Enfermedades del Sistema Nervioso/líquido cefalorraquídeo , Proteínas Represoras/genética , Tetrahidrofolatos/líquido cefalorraquídeo , Células Cultivadas , Regulación hacia Abajo , Femenino , Receptor 1 de Folato/deficiencia , Deficiencia de Ácido Fólico/genética , Células HEK293 , Humanos , Masculino , Enfermedades del Sistema Nervioso/genética , Distrofias Neuroaxonales , Linaje , Análisis de Secuencia de ADNRESUMEN
Neural tube closure is a critical early step in central nervous system development that requires precise control of metabolism to ensure proper cellular proliferation and differentiation. Dysregulation of glucose metabolism during pregnancy has been associated with neural tube closure defects (NTDs) in humans suggesting that the developing neuroepithelium is particularly sensitive to metabolic changes. However, it remains unclear how metabolic pathways are regulated during neurulation. Here, we used single-cell mRNA-sequencing to analyze expression of genes involved in metabolism of carbon, fats, vitamins, and antioxidants during neurulation in mice and identify a coupling of glycolysis and cellular proliferation to ensure proper neural tube closure. Using loss of miR-302 as a genetic model of cranial NTD, we identify misregulated metabolic pathways and find a significant upregulation of glycolysis genes in embryos with NTD. These findings were validated using mass spectrometry-based metabolite profiling, which identified increased glycolytic and decreased lipid metabolites, consistent with a rewiring of central carbon traffic following loss of miR-302. Predicted miR-302 targets Pfkp, Pfkfb3, and Hk1 are significantly upregulated upon NTD resulting in increased glycolytic flux, a shortened cell cycle, and increased proliferation. Our findings establish a critical role for miR-302 in coordinating the metabolic landscape of neural tube closure.
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Ciclo Celular , Glucólisis , MicroARNs/metabolismo , Tubo Neural/metabolismo , Neurulación , Animales , Células Cultivadas , Hexoquinasa/genética , Hexoquinasa/metabolismo , Ratones , Ratones Endogámicos C57BL , MicroARNs/genética , Tubo Neural/embriología , Fosfofructoquinasa-1 Tipo C/genética , Fosfofructoquinasa-1 Tipo C/metabolismo , Fosfofructoquinasa-2/genética , Fosfofructoquinasa-2/metabolismoRESUMEN
Neural tube defects (NTDs) are a group of severe congenital malformations caused by a failure of neural tube closure during early embryonic development. Although extensively investigated, the genetic etiology of NTDs remains poorly understood. FKBP8 is critical for proper mammalian neural tube closure. Fkbp8-/- mouse embryos showed posterior NTDs consistent with a diagnosis of spina bifida (SB). To date, no publication has reported any association between FKBP8 and human NTDs. Using Sanger sequencing on genomic DNA samples from 472 SB and 565 control samples, we identified five rare (MAF ≤ 0.001) deleterious variants in SB patients, while no rare deleterious variant was identified in the controls (P = 0.0191). p.Glu140* affected FKBP8 localization to the mitochondria and created a truncated form of the FKBP8 protein, thus impairing its interaction with BCL2 and ultimately leading to an increase in cellular apoptosis. p.Ser3Leu, p.Lys315Asn and p.Ala292Ser variants decreased FKBP8 protein level. p.Lys315Asn further increased the cellular apoptosis. RNA sequencing on anterior and posterior tissues isolated from Fkbp8-/- and wildtype mice at E9.5 and E10.5 showed that Fkbp8-/- embryos have an abnormal expression profile within tissues harvested at posterior sites, thus leading to a posterior NTD. Moreover, we found that Fkbp8 knockout mouse embryos have abnormal expression of Wnt3a and Nkx2.9 during the early stage of neural tube development, perhaps also contributing to caudal specific NTDs. These findings provide evidence that functional variants of FKBP8 are risk factors for SB, which may involve a novel mechanism by which Fkbp8 mutations specifically cause SB in mice.
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Proteínas de Homeodominio/genética , Disrafia Espinal/genética , Proteínas de Unión a Tacrolimus/genética , Factores de Transcripción/genética , Proteína Wnt3A/genética , Animales , Apoptosis/genética , Femenino , Predisposición Genética a la Enfermedad , Humanos , Recién Nacido , Masculino , Ratones , Ratones Noqueados , Malformaciones del Sistema Nervioso , Defectos del Tubo Neural/genética , Defectos del Tubo Neural/patología , Factores de Riesgo , Disrafia Espinal/patologíaRESUMEN
Neural tube defects (NTDs) are a broad class of congenital birth defects that result from the failure of neural tube closure during neurulation. Folic acid supplementation has been shown to prevent the occurrence of NTDs by as much as 70% in some human populations, and folate deficiency in a pregnant woman is associated with increased risk for having an NTD affected infant. Thus, folate transport-related genes and genes involved in the subsequent folate-mediated one-carbon metabolic pathway have long been considered primary candidates to study the genetic etiology of human NTDs. Herein, we review the genes involved in folate transport and one-carbon metabolism thus far identified as contributing variants that influence human NTD risk, and place these findings in the context of our evolving understanding of the complex genetic architecture underlying these defects.
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Transporte Biológico/genética , Deficiencia de Ácido Fólico/genética , Ácido Fólico/metabolismo , Redes y Vías Metabólicas/genética , Defectos del Tubo Neural/genética , Femenino , Humanos , EmbarazoRESUMEN
DNA damage response (DDR) genes orchestrating the network of DNA repair, cell cycle control, are essential for the rapid proliferation of neural progenitor cells. To date, the potential association between specific DDR genes and the risk of human neural tube defects (NTDs) has not been investigated. Using whole-genome sequencing and targeted sequencing, we identified significant enrichment of rare deleterious RAD9B variants in spina bifida cases compared to controls (8/409 vs. 0/298; p = .0241). Among the eight identified variants, the two frameshift mutants and p.Gln146Glu affected RAD9B nuclear localization. The two frameshift mutants also decreased the protein level of RAD9B. p.Ser354Gly, as well as the two frameshifts, affected the cell proliferation rate. Finally, p.Ser354Gly, p.Ser10Gly, p.Ile112Met, p.Gln146Glu, and the two frameshift variants showed a decreased ability for activating JNK phosphorylation. RAD9B knockdowns in human embryonic stem cells profoundly affected early differentiation through impairing PAX6 and OCT4 expression. RAD9B deficiency impeded in vitro formation of neural organoids, a 3D cell culture model for human neural development. Furthermore, the RNA-seq data revealed that loss of RAD9B dysregulates cell adhesion genes during organoid formation. These results represent the first demonstration of a DDR gene as an NTD risk factor in humans.
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Proteínas de Ciclo Celular/deficiencia , Predisposición Genética a la Enfermedad , Defectos del Tubo Neural/genética , Disrafia Espinal/genética , Estudios de Casos y Controles , Línea Celular , Daño del ADN , Reparación del ADN , Células Madre Embrionarias/metabolismo , Técnica del Anticuerpo Fluorescente , Expresión Génica , Humanos , Mutación con Pérdida de Función , Mutación , Defectos del Tubo Neural/diagnóstico , Neuronas/metabolismo , Medición de Riesgo , Factores de Riesgo , Disrafia Espinal/diagnósticoRESUMEN
Optimal functioning of neuronal networks is critical to the complex cognitive processes of memory and executive function that deteriorate in Alzheimer's disease (AD). Here we use cellular and animal models as well as human biospecimens to show that AD-related stressors mediate global disturbances in dynamic intra- and inter-neuronal networks through pathologic rewiring of the chaperome system into epichaperomes. These structures provide the backbone upon which proteome-wide connectivity, and in turn, protein networks become disturbed and ultimately dysfunctional. We introduce the term protein connectivity-based dysfunction (PCBD) to define this mechanism. Among most sensitive to PCBD are pathways with key roles in synaptic plasticity. We show at cellular and target organ levels that network connectivity and functional imbalances revert to normal levels upon epichaperome inhibition. In conclusion, we provide proof-of-principle to propose AD is a PCBDopathy, a disease of proteome-wide connectivity defects mediated by maladaptive epichaperomes.
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Enfermedad de Alzheimer/metabolismo , Hipocampo/metabolismo , Plasticidad Neuronal/fisiología , Proteoma/metabolismo , Enfermedad de Alzheimer/patología , Animales , Encéfalo/patología , Mapeo Encefálico , Disfunción Cognitiva/metabolismo , Función Ejecutiva/fisiología , Femenino , Hipocampo/patología , Humanos , Masculino , Memoria/fisiología , Ratones , Vías NerviosasRESUMEN
BACKGROUND/PURPOSE: In 2004, a heritable occurrence of spina bifida was reported in sheep on a farm in the United States. We maintained and characterized the spina bifida phenotype in this flock to assess its potential as an alternative surgical model. METHODS: A breeding strategy was developed in which the sheep were crossed to maintain or increase the occurrence of spina bifida. Measurements and observations were recorded regarding lesion size, birthweight, ambulatory capacity, or urological function, and necropsies were performed on spina bifida afflicted lambs in conjunction with magnetic resonance imaging to determine the character of the spina bifida defects and assess the presence of Chiari-like malformations or hydrocephalus. RESULTS: The defects were observed to be more prevalent in ram lambs, and the rate of spina bifida per litter could be increased through backcrossing or by selection of a productive ewe breed. The lambs displayed a range of ambulatory and urological deficits which could be used to evaluate new fetal repair methodologies. Finally, affected lambs were shown to demonstrate severe Chiari malformations and hydrocephalus. CONCLUSIONS: We have determined that use of these sheep as a natural source for spina bifida fetuses is feasible and could supplement the deficits of current sheep models for myelomeningocele repair. LEVEL OF EVIDENCE: Level IV.
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Modelos Animales de Enfermedad , Fetoscopía , Meningomielocele , Disrafia Espinal , Animales , Femenino , Meningomielocele/genética , Meningomielocele/patología , Meningomielocele/cirugía , Embarazo , Ovinos , Disrafia Espinal/patología , Disrafia Espinal/cirugíaRESUMEN
OBJECTIVE: Maternal folate (vitamin B9) status is the largest known modifier of neural tube defect risk, so we evaluated folate-related mechanisms of action for dolutegravir (DTG) developmental toxicity. DESIGN: Folate receptor 1 (FOLR1) was examined as a target for DTG developmental toxicity using protein and cellular interaction studies and an animal model. METHODS: FOLR1 competitive binding studies were used to test DTG for FOLR1 antagonism. Human placenta cell line studies were used to test interactions with DTG, folate, and cations. Zebrafish were selected as an animal model to examine DTG-induced developmental toxicity and rescue strategies. RESULTS: FOLR1 binding studies indicate DTG is a noncompetitive FOLR1 antagonist at therapeutic concentrations. In-vitro testing indicates calcium (2âmmol/l) increases FOLR1-folate interactions and alters DTG-FOLR1-folate interactions and cytotoxicity. DTG does not inhibit downstream folate metabolism by dihydrofolate reductase. Early embryonic exposure to DTG is developmentally toxic in zebrafish, and supplemental folic acid can mitigate DTG developmental toxicity. CONCLUSION: Folates and FOLR1 are established modifiers of risk for neural tube defects, and binding data indicates DTG is a partial antagonist of FOLR1. Supplemental folate can ameliorate increased developmental toxicity due to DTG in zebrafish. The results from these studies are expected to inform and guide future animal models and clinical studies of DTG-based antiretroviral therapy in women of childbearing age.
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Receptor 1 de Folato/antagonistas & inhibidores , Ácido Fólico/administración & dosificación , Compuestos Heterocíclicos con 3 Anillos/toxicidad , Proteínas de Pez Cebra/antagonistas & inhibidores , Pez Cebra/embriología , Animales , Línea Celular , Suplementos Dietéticos , Desarrollo Embrionario/efectos de los fármacos , Femenino , Receptor 1 de Folato/genética , Infecciones por VIH/tratamiento farmacológico , Inhibidores de Integrasa VIH/toxicidad , Humanos , Modelos Animales , Oxazinas , Piperazinas , Embarazo , Piridonas , Pruebas de Toxicidad , Pez Cebra/genética , Proteínas de Pez Cebra/genéticaRESUMEN
Data generated in Niemann Pick type C1 (NPC1) human embryonic and human induced pluripotent stem cell derived neurons complement on-going studies in animal models and provide the first example, in disease-relevant human cells, of processes that underlie preferential neuronal defects in a NPC1. Our work and that of other investigators in human neurons derived from stem cells highlight the importance of performing rigorous mechanistic studies in relevant cell types to guide drug discovery and therapeutic development, alongside of existing animal models. Through the use of human stem cell-derived models of disease, we can identify and discover or repurpose drugs that revert early events that lead to neuronal failure in NPC1. Together with the study of disease pathogenesis and efficacy of therapies in animal models, these strategies will fulfill the promise of stem cell technology in the development of new treatments for human diseases. This article is part of a Special Issue entitled SI: Exploiting human neurons.
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Células Madre Embrionarias/fisiología , Células Madre Pluripotentes Inducidas/fisiología , Enfermedad de Niemann-Pick Tipo C/fisiopatología , Animales , Descubrimiento de Drogas , Células Madre Embrionarias/efectos de los fármacos , Humanos , Células Madre Pluripotentes Inducidas/efectos de los fármacos , Enfermedad de Niemann-Pick Tipo C/tratamiento farmacológicoRESUMEN
BACKGROUND: Recent studies have implicated specific assembly subtypes of ß-amyloid (Aß) peptide, specifically soluble oligomers (soAß) as disease-relevant structures that may underlie memory loss in Alzheimer disease. Removing existing soluble and insoluble Aß assemblies is thought to be essential for any attempt at stabilizing brain function and slowing cognitive decline in Alzheimer disease. IV immunoglobulin (IVIg) therapies have been shown to contain naturally occurring polyclonal antibodies that recognize conformational neoepitopes of soluble or insoluble Aß assemblies including soAß. These naturally occurring polyclonal antibodies have been suggested to underlie the apparent clinical benefits of IVIg. However, direct evidence linking anti-Aß antibodies to the clinical bioactivity of IVIg has been lacking. METHODS: Five-month-old female Dutch APP E693Q mice were treated for 3 months with neat IVIg or with IVIg that had been affinity-depleted over immobilized Aß conformers in 1 of 2 assembly states. Memory was assessed in a battery of tests followed by quantification of brain soAß levels using standard anti-soAß antibodies. RESULTS: We provide evidence that NU4-type soAß (NU4-soAß) assemblies accumulate in the brains of Dutch APP E693Q mice and are associated with defects in memory, even in the absence of insoluble Aß plaques. Memory benefits were associated with depletion from APP E693Q mouse brain of NU4-soAß and A11-soAß but not OC-type fibrillar Aß oligomers. CONCLUSIONS: We propose that targeting of specific soAß assembly subtypes may be an important consideration in the therapeutic and/or prophylactic benefit of anti-Aß antibody drugs.
RESUMEN
The presenilin 1 (PSEN1) L271V mutation causes early-onset familial Alzheimer's disease by disrupting the alternative splicing of the PSEN1 gene, producing some transcripts harboring the L271V point mutation and other transcripts lacking exon 8 (PS1(∆exon8)). We previously reported that PS1 L271V increased amyloid beta (Aß) 42/40 ratios, while PS1(∆exon8) reduced Aß42/40 ratios, indicating that the former and not the exon 8 deletion transcript is amyloidogenic. Also, PS1(∆exon8) did not rescue Aß generation in PS1/2 double knockout cells indicating its identity as a severe loss-of-function splice form. PS1(∆exon8) is generated physiologically raising the possibility that we had identified the first physiological inactive PS1 isoform. We studied PS1(∆exon8) in vivo by crossing PS1(∆exon8) transgenics with either PS1-null or Dutch APP(E693Q) mice. As a control, we crossed APP(E693Q) with mice expressing a deletion in an adjacent exon (PS1(∆exon9)). PS1(∆exon8) did not rescue embryonic lethality or Notch-deficient phenotypes of PS1-null mice displaying severe loss of function in vivo. We also demonstrate that this splice form can interact with wildtype PS1 using cultured cells and co-immunoprecipitation (co-IP)/bimolecular fluorescence complementation. Further co-IP demonstrates that PS1(∆exon8) interacts with nicastrin, participating in the γ-secretase complex formation. These data support that catalytically inactive PS1(∆exon8) is generated physiologically and participates in protein-protein interactions.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/metabolismo , Exones/genética , Glicoproteínas de Membrana/metabolismo , Presenilina-1/genética , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/fisiopatología , Péptidos beta-Amiloides/genética , Animales , Encéfalo/metabolismo , Embrión de Mamíferos/metabolismo , Retículo Endoplásmico/metabolismo , Fluorescencia , Células HEK293 , Humanos , Inmunoprecipitación , Ratones Noqueados , Actividad Motora , Fenotipo , Placa Amiloide/metabolismo , Placa Amiloide/patología , Presenilina-1/deficiencia , Presenilina-1/metabolismo , Unión Proteica , Eliminación de Secuencia/genética , TransgenesRESUMEN
BACKGROUND AND PURPOSE: In this study, we demonstrate the use of Molecular topology (MT) in an Alzheimer's disease (AD) drug discovery program. MT uses and expands upon the principles governing the molecular connectivity theory of numerically characterizing molecular structures, in the present case, active anti-AD drugs/agents, using topological descriptors to build models. Topological characterization has been shown to embody sufficient molecular information to provide strong correlation to therapeutic efficacy. EXPERIMENTAL APPROACH: We used MT to include multiple bioactive properties that allows for the identification of multi-functional single agent compounds, in this case, the dual functions of ß-amyloid (Aß) -lowering and anti-oligomerization. Using this technology, we identified and designed novel compounds in chemical classes unrelated to current anti-AD agents that exert dual Aß lowering and anti-Aß oligomerization activities in animal models of AD. AD is a multifaceted disease with different pathological features. CONCLUSION AND IMPLICATIONS: Our study, for the first time, demonstrated that MT can provide novel strategy for discovering drugs with Aß lowering and anti-aggregation dual activities for AD.