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Cárdenas AM, Fernández-Olivares P, Díaz-Franulic I, González-Jamett AM, Shimahara T, Segura-Aguilar J, Caviedes R, Caviedes P. Knockdown of Myo-Inositol Transporter SMIT1 Normalizes Cholinergic and Glutamatergic Function in an Immortalized Cell Line Established from the Cerebral Cortex of a Trisomy 16 Fetal Mouse, an Animal Model of Human Trisomy 21 (Down Syndrome). Neurotox Res 2017; 32:614-623. [PMID: 28695546 DOI: 10.1007/s12640-017-9775-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/21/2017] [Accepted: 06/28/2017] [Indexed: 12/31/2022]
Abstract
The Na+/myo-inositol cotransporter (SMIT1) is overexpressed in human Down syndrome (DS) and in trisomy 16 fetal mice (Ts16), an animal model of the human condition. SMIT1 overexpression determines increased levels of intracellular myo-inositol, a precursor of phophoinositide synthesis. SMIT1 is overexpressed in CTb cells, an immortalized cell line established from the cerebral cortex of a Ts16 mouse fetus. CTb cells exhibit impaired cytosolic Ca2+ signals in response to glutamatergic and cholinergic stimuli (increased amplitude and delayed time-dependent kinetics in the decay post-stimulation), compared to our CNh cell line, derived from the cerebral cortex of a euploid animal. Considering the role of myo-inositol in intracellular signaling, we normalized SMIT1 expression in CTb cells using specific mRNA antisenses. Forty-eight hours post-transfection, SMIT1 levels in CTb cells reached values comparable to those of CNh cells. At this time, decay kinetics of Ca2+ signals induced by either glutamate, nicotine, or muscarine were accelerated in transfected CTb cells, to values similar to those of CNh cells. The amplitude of glutamate-induced cytosolic Ca2+ signals in CTb cells was also normalized. The results suggest that SMIT1 overexpression contributes to abnormal cholinergic and glutamatergic Ca2+ signals in the trisomic condition, and knockdown of DS-related genes in our Ts16-derived cell line could constitute a relevant tool to study DS-related neuronal dysfunction.
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Affiliation(s)
- Ana María Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Paola Fernández-Olivares
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Program of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Clasificador 7, Independencia, 1027, Santiago, Chile
| | - Ignacio Díaz-Franulic
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Center for Bioinformatics and Integrative Biology, Universidad Andrés Bello, Santiago, Chile
- Fundación Fraunhofer Chile, Las Condes, Chile
| | - Arlek M González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | | | - Juan Segura-Aguilar
- Program of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Clasificador 7, Independencia, 1027, Santiago, Chile
| | - Raúl Caviedes
- Program of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Clasificador 7, Independencia, 1027, Santiago, Chile
| | - Pablo Caviedes
- Program of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Clasificador 7, Independencia, 1027, Santiago, Chile.
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Rapoport SI, Primiani CT, Chen CT, Ahn K, Ryan VH. Coordinated Expression of Phosphoinositide Metabolic Genes during Development and Aging of Human Dorsolateral Prefrontal Cortex. PLoS One 2015; 10:e0132675. [PMID: 26168237 PMCID: PMC4500567 DOI: 10.1371/journal.pone.0132675] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 06/17/2015] [Indexed: 01/10/2023] Open
Abstract
Background Phosphoinositides, lipid-signaling molecules, participate in diverse brain processes within a wide metabolic cascade. Hypothesis Gene transcriptional networks coordinately regulate the phosphoinositide cascade during human brain Development and Aging. Methods We used the public BrainCloud database for human dorsolateral prefrontal cortex to examine age-related expression levels of 49 phosphoinositide metabolic genes during Development (0 to 20+ years) and Aging (21+ years). Results We identified three groups of partially overlapping genes in each of the two intervals, with similar intergroup correlations despite marked phenotypic differences between Aging and Development. In each interval, ITPKB, PLCD1, PIK3R3, ISYNA1, IMPA2, INPPL1, PI4KB, and AKT1 are in Group 1, PIK3CB, PTEN, PIK3CA, and IMPA1 in Group 2, and SACM1L, PI3KR4, INPP5A, SYNJ1, and PLCB1 in Group 3. Ten of the genes change expression nonlinearly during Development, suggesting involvement in rapidly changing neuronal, glial and myelination events. Correlated transcription for some gene pairs likely is facilitated by colocalization on the same chromosome band. Conclusions Stable coordinated gene transcriptional networks regulate brain phosphoinositide metabolic pathways during human Development and Aging.
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Affiliation(s)
- Stanley I. Rapoport
- Brain Physiology and Metabolism Section, Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Bethesda, MD, United States of America
- * E-mail:
| | - Christopher T. Primiani
- Brain Physiology and Metabolism Section, Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Bethesda, MD, United States of America
| | - Chuck T. Chen
- Section on Nutritional Neurosciences, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, United States of America
| | - Kwangmi Ahn
- Child Psychiatry Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States of America
| | - Veronica H. Ryan
- Brain Physiology and Metabolism Section, Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Bethesda, MD, United States of America
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Bathena SP, Huang J, Epstein AA, Gendelman HE, Boska MD, Alnouti Y. Rapid and reliable quantitation of amino acids and myo-inositol in mouse brain by high performance liquid chromatography and tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 893-894:15-20. [PMID: 22425384 DOI: 10.1016/j.jchromb.2012.01.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 01/10/2012] [Accepted: 01/29/2012] [Indexed: 10/28/2022]
Abstract
Amino acids and myo-inositol have long been proposed as putative biomarkers for neurodegenerative diseases. Accurate measures and stability have precluded their selective use. To this end, a sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method based on multiple reaction monitoring was developed to simultaneously quantify glutamine, glutamate, γ-aminobutyric acid (GABA), aspartic acid, N-acetyl aspartic acid, taurine, choline, creatine, phosphocholine and myo-inositol in mouse brain by methanol extractions. Chromatography was performed using a hydrophilic interaction chromatography silica column within in a total run time of 15 min. The validated method is selective, sensitive, accurate, and precise. The method has a limit of quantification ranging from 2.5 to 20 ng/ml for a range of analytes and a dynamic range from 2.5-20 to 500-4000 ng/ml. This LC-MS/MS method was validated for biomarker discovery in models of human neurological disorders.
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Affiliation(s)
- Sai P Bathena
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198, USA
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4
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Two major inositol transporters and their role in cryptococcal virulence. EUKARYOTIC CELL 2011; 10:618-28. [PMID: 21398509 DOI: 10.1128/ec.00327-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cryptococcus neoformans is an AIDS-associated human fungal pathogen and the most common cause of fungal meningitis, with a mortality rate over 40% in AIDS patients. Significant advances have been achieved in understanding its disease mechanisms. Yet the underlying mechanism of a high frequency of cryptococcal meningitis remains unclear. The existence of high inositol concentrations in brain and our earlier discovery of a large inositol transporter (ITR) gene family in C. neoformans led us to investigate the potential role of inositol in Cryptococcus-host interactions. In this study, we focus on functional analyses of two major ITR genes to understand their role in virulence of C. neoformans. Our results show that ITR1A and ITR3C are the only two ITR genes among 10 candidates that can complement the growth defect of a Saccharomyces cerevisiae strain lacking inositol transporters. Both S. cerevisiae strains heterologously expressing ITR1A or ITR3C showed high inositol uptake activity, an indication that they are major inositol transporters. Significantly, itr1a itr3c double mutants showed significant virulence attenuation in murine infection models. Mutating both ITR1A and ITR3C in an ino1 mutant background activates the expression of several remaining ITR candidates and does not show more severe virulence attenuation, suggesting that both inositol uptake and biosynthetic pathways are important for inositol acquisition. Overall, our study provides evidence that host inositol and fungal inositol transporters are important for Cryptococcus pathogenicity.
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Cramer NP, Best TK, Stoffel M, Siarey RJ, Galdzicki Z. GABAB–GIRK2-Mediated Signaling in Down Syndrome. GABABRECEPTOR PHARMACOLOGY - A TRIBUTE TO NORMAN BOWERY 2010; 58:397-426. [DOI: 10.1016/s1054-3589(10)58015-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Azab AN, He Q, Ju S, Li G, Greenberg ML. Glycogen synthase kinase‐3 is required for optimalde novosynthesis of inositol. Mol Microbiol 2007; 63:1248-58. [PMID: 17257308 DOI: 10.1111/j.1365-2958.2007.05591.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Studies have shown that the inositol biosynthetic pathway and the enzyme glycogen synthase kinase-3 (GSK-3) are targets of the mood-stabilizing drugs lithium and valproate. However, a relationship between these targets has not been previously described. We hypothesized that GSK-3 may play a role in inositol synthesis, and that loss of GSK-3 may lead to inositol depletion, thus providing a mechanistic link between the two drug targets. Utilizing a yeast Saccharomyces cerevisiae gsk-3Delta quadruple-null mutant, in which all four genes encoding homologues of mammalian GSK-3 are disrupted, we tested the hypothesis that GSK-3 is required for de novo inositol biosynthesis. The gsk-3Delta mutant exhibited multiple features of inositol depletion, including defective growth in inositol-lacking medium, decreased intracellular inositol, increased INO1 and ITR1 expression, and decreased levels of phosphatidylinositol. Treatment of wild-type cells with a highly specific GSK-3 inhibitor led to a significant increase in INO1 expression. Supplementation with inositol alleviated the temperature sensitivity of gsk-3Delta. Activity of myo-inositol-3 phosphate synthase, the rate-limiting enzyme in inositol de novo biosynthesis, was decreased in gsk-3Delta. These results demonstrate for the first time that GSK-3 is required for optimal myo-inositol-3 phosphate synthase activity and de novo inositol biosynthesis, and that loss of GSK-3 activity causes inositol depletion.
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Affiliation(s)
- Abed N Azab
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
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Saud K, Arriagada C, Cárdenas AM, Shimahara T, Allen DD, Caviedes R, Caviedes P. Neuronal dysfunction in Down syndrome: contribution of neuronal models in cell culture. ACTA ACUST UNITED AC 2006; 99:201-10. [PMID: 16646156 DOI: 10.1016/j.jphysparis.2005.12.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Down syndrome (DS) in humans, or trisomy of autosome 21, represents the hyperdiploidy that most frequently survives gestation, reaching an incidence of 1 in 700 live births. The condition is associated with multisystemic anomalies, including those affecting the central nervous system (CNS), determining a characteristic mental retardation. At a neuronal level, our group and others have shown that the condition determines marked alterations of action potential and ionic current kinetics, which may underlie abnormal processing of information by the CNS. Since the use of human tissue presents both practical and ethical problems, animal models of the human condition have been sought. Murine trisomy 16 (Ts16) is a model of the human condition, due to the great homology between human autosome 21 and murine 16. Both conditions share the same alterations of electrical membrane properties. However, the murine Ts16 condition is unviable (animals die in utero), thus limiting the quantity of tissue procurable. To overcome this obstacle, we have established immortal cell lines from normal and Ts16 mice with a method developed by our group that allows the stable in vitro immortalization of mammalian tissue, yielding cell lines which retain the characteristics of the originating cells. Cell lines derived from cerebral cortex, hippocampus, spinal cord and dorsal root ganglion of Ts16 animals show alterations of intracellular Ca2+ signals in response to several neurotransmitters (glutamate, acetylcholine, and GABA). Gene overdose most likely underlies these alterations in cell function, and the identification of the relative contribution of DS associated genes on such specific neuronal dysfunction should be investigated. This could enlighten our understanding on the contribution of these genes in DS, and identify new therapeutic targets.
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Affiliation(s)
- Katherine Saud
- Program of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Independencia, Santiago, Chile
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Guan G, Dai P, Shechter I. cDNA cloning and gene expression analysis of human myo-inositol 1-phosphate synthase. Arch Biochem Biophys 2003; 417:251-9. [PMID: 12941308 DOI: 10.1016/s0003-9861(03)00388-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
myo-Inositol 1-phosphate synthase (EC 5.5.1.4) (IPS) is a key enzyme in myo-inositol biosynthesis pathway. This study describes the molecular cloning of the full length human myo-inositol 1-phosphate synthase (hIPS) cDNA, tissue distribution of its mRNA and characterizes its gene expression in cultured HepG2 cells. Human testis, ovary, heart, placenta, and pancreas express relatively high level of hIPS mRNA, while blood leukocyte, thymus, skeletal muscle, and colon express low or marginal amount of the mRNA. In the presence of glucose, hIPS mRNA level increases 2- to 4-fold in HepG2 cells. hIPS mRNA is also up-regulated 2- to 3-fold by 2.5 microM lovastain. This up-regulation is prevented by mevalonic acid, farnesol, and geranylgeraniol, suggesting a G-protein mediated signal transduction mechanism in the regulation of hIPS gene expression. hIPS mRNA expression is 50% suppressed by 10mM lithium ion in these cells. Neither 5mM myo-inositol nor the three hormones: estrogen, thyroid hormone, and insulin altered hIPS mRNA expression in these cells.
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Affiliation(s)
- Guimin Guan
- Department of Surgery, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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Chikhale EG, Balbo A, Galdzicki Z, Rapoport SI, Shetty HU. Measurement of myo-inositol turnover in phosphatidylinositol: description of a model and mass spectrometric method for cultured cortical neurons. Biochemistry 2001; 40:11114-20. [PMID: 11551209 DOI: 10.1021/bi010817k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rates of myo-inositol (Ins) incorporation and turnover in phosphatidylinositol (PtdIns) were determined in cultured mouse cortical neurons. Cells were incubated with deuterium-labeled myo-inositol (Ins) in culture medium free of unlabeled Ins. The time-dependent changes in the specific activity of cytosolic Ins and membrane PtdIns were measured by mass spectrometry. PtdIns turnover was modeled incorporating values for Ins flux, cytosolic dilution, PtdIns concentration, and rate of incorporation into PtdIns. Recycled Ins diluted the labeled precursor pool, and a time course was obtained for this cytosolic process. The specific activity of the precursor pool at the plateau of the time-course curve was 0.43 +/- 0.04 (mean +/- SD). The incorporation of the tracer into PtdIns was linear between 4 and 10 h incubation of the neurons. After factoring in the extent of dilution of the tracer in the precursor pool, the rate of Ins incorporation into PtdIns was found to be 315 +/- 51 nmol (g of protein)(-1) x h(-1). The half-life of Ins in PtdIns was calculated for each point on the linear incorporation curve and then corrected for the tracer reincorporation. The half-life of Ins in PtdIns was 6.7 +/- 0.2 h, which translates into a basal turnover rate of 10.3%/h in this in vitro system. The mathematical model and the stable isotope method described here should allow assessment of the dynamics of PtdIns signaling altered in certain diseases or by agents.
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Affiliation(s)
- E G Chikhale
- Section on Brain Physiology and Metabolism, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892, USA
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10
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Galdzicki Z, Siarey R, Pearce R, Stoll J, Rapoport SI. On the cause of mental retardation in Down syndrome: extrapolation from full and segmental trisomy 16 mouse models. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2001; 35:115-45. [PMID: 11336779 DOI: 10.1016/s0926-6410(00)00074-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Down syndrome (DS, trisomy 21, Ts21) is the most common known cause of mental retardation. In vivo structural brain imaging in young DS adults, and post-mortem studies, indicate a normal brain size after correction for height, and the absence of neuropathology. Functional imaging with positron emission tomography (PET) shows normal brain glucose metabolism, but fewer significant correlations between metabolic rates in different brain regions than in controls, suggesting reduced functional connections between brain circuit elements. Cultured neurons from Ts21 fetuses and from fetuses of an animal model for DS, the trisomy 16 (Ts16) mouse, do not differ from controls with regard to passive electrical membrane properties, including resting potential and membrane resistance. On the other hand, the trisomic neurons demonstrate abnormal active electrical and biochemical properties (duration of action potential and its rates of depolarization and repolarization, altered kinetics of active Na(+), Ca(2+) and K(+) currents, altered membrane densities of Na(+) and Ca(2+) channels). Another animal model, the adult segmental trisomy 16 mouse (Ts65Dn), demonstrates reduced long-term potentiation and increased long-term depression (models for learning and memory related to synaptic plasticity) in the CA1 region of the hippocampus. Evidence suggests that the abnormalities in the trisomy mouse models are related to defective signal transduction pathways involving the phosphoinositide cycle, protein kinase A and protein kinase C. The phenotypes of DS and its mouse models do not involve abnormal gene products due to mutations or deletions, but result from altered expression of genes on human chromosome 21 or mouse chromosome 16, respectively. To the extent that the defects in signal transduction and in active electrical properties, including synaptic plasticity, that are found in the Ts16 and Ts65Dn mouse models, are found in the brain of DS subjects, we postulate that mental retardation in DS results from such abnormalities. Changes in timing and synaptic interaction between neurons during development can lead to less than optimal functioning of neural circuitry and signaling then and in later life.
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Affiliation(s)
- Z Galdzicki
- Section on Brain Physiology and Metabolism, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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Yao FS, Caserta MT, Wyrwicz AM. In vitro 1H and 31P NMR spectroscopic evidence of multiple aberrant biochemical pathways in murine trisomy 16 brain development. Int J Dev Neurosci 2000; 18:833-41. [PMID: 11154853 DOI: 10.1016/s0736-5748(00)00043-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy was used to evaluate cytosolic compounds and membrane phospholipids simultaneously in trisomy 16 (Ts16) and euploid (control) murine brain at fetal day 15 in order to examine the cellular biochemistry that underlies the neurodevelopmental consequences of chromosome triplication in this model of Down syndrome (DS). Proton NMR spectroscopic analysis of brain tissue extracts demonstrated decreased levels of choline and increased levels of myo-inositol (MI) in Ts16 brains compared with control. These data are consistent with the cholinergic deficits and elevated MI levels previously described in Ts16. Compared with euploid brains. Ts16 brains also possess higher levels of creatine, adenosine, and tyrosine. Increased levels of MI and creatine, compounds that are localized to glia, imply abnormalities in the trophic environment of Ts16 brain. Phosphorus NMR spectroscopic analysis of extracts further revealed elevated levels of anionic phospholipid membrane components, such as phosphatidylinositol (PtdIno) and phosphatidylethanolamine, in Ts16 brains. Since these compounds are confined to the inner leaflet of the membrane, the findings suggest that membrane composition is altered specifically in the cytosolic bilayer at this stage. Together our proton and phosphorus NMR spectroscopic results indicate that multiple biochemical pathways are affected in Ts16 brain development. Understanding the effects of these aberrations may elucidate the processes that lead to neural dysfunction and Alzheimer's disease (AD) neuropathology in DS individuals.
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Affiliation(s)
- F S Yao
- Department of Psychiatry and Behavioral Sciences, Northwestern University Medical School, Chicago, IL 60611, USA.
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12
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Abstract
The Na+/myo-inositol cotransporter (SLC5A3) gene, located on the long arm of human chromosome 21, may play a key role in osmoregulation including the regulation of levels of the "idiogenic osmole," myo-inositol, in brain cells. To determine whether the levels of myo-inositol are increased in the basal ganglia of children with Down syndrome, we performed in vivo brain hydrogen 1-nuclear magnetic resonance or 1H-magnetic resonance spectroscopy and measured plasma osmolality in a cohort of children with trisomy 21. Myo-inositol is elevated in the corpus striatum of infants and children with Down syndrome, even in the absence of hypertonic stress.
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Affiliation(s)
- G T Berry
- Department of Pediatrics, University of Pennsylvania School of Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
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13
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Abstract
Autosomal trisomy causes a large proportion of all human pregnancy loss and so is a significant source of lethality in the human population. The autosomal trisomy syndromes each have a different phenotype and are probably caused by the effects of specific genes that are present in three copies, rather than the normal two. Identifying these genes will require the application of classical genetic and new genome-manipulation approaches. Recent advances in chromosome engineering are now allowing us to create precisely defined autosomal trisomies in the mouse, and so provide new routes to identifying the critical, dosage-sensitive genes that are responsible for these highly deleterious, yet very common, syndromes.
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Affiliation(s)
- D Hernandez
- Department of Neurogenetics, Imperial College School of Medicine (St Mary's), Norfolk Place, London, UK W2 1PG.
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Siarey RJ, Stoll J, Rapoport SI, Galdzicki Z. Altered long-term potentiation in the young and old Ts65Dn mouse, a model for Down Syndrome. Neuropharmacology 1997; 36:1549-54. [PMID: 9517425 DOI: 10.1016/s0028-3908(97)00157-3] [Citation(s) in RCA: 186] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We investigated the phenomenon of long-term potentiation (LTP) in a genetic model of Down Syndrome, the segmental trisomy mouse (Ts65Dn). Ts65Dn mice survive to adulthood and have an extra chromosome that contains a segment of chromosome 16 homologous to human chromosome 21. In this study, field excitatory postsynaptic potentials (fEPSP) were recorded from the CA1 area of in vitro hippocampal slices from diploid and Ts65Dn mice, and LTP was induced by a single tetanizing pulse train (1 sec in duration) at 100 Hz. The hippocampus from both young (2 months) and older (9 months) Ts65Dn mice had a reduced LTP over a period of 60 min compared with LTP in age-matched controls. This finding may explain the reported behavioral and learning impairments in Ts65Dn mice; it suggests that this mouse model can be used to study the role of altered synaptic plasticity in mental retardation of Down Syndrome.
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Affiliation(s)
- R J Siarey
- Laboratory of Neurosciences, NIA, NIH, Bethesda, MD 20892, USA
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