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Distinct Basal Metabolism in Three Mouse Models of Neurodevelopmental Disorders. eNeuro 2021; 8:ENEURO.0292-20.2021. [PMID: 33820803 PMCID: PMC8174051 DOI: 10.1523/eneuro.0292-20.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 02/27/2021] [Accepted: 03/15/2021] [Indexed: 02/06/2023] Open
Abstract
Prevalence of metabolic disturbances is higher among individuals with neurodevelopmental disorders (NDDs), yet this association has been largely overlooked. Investigation into human disease remains challenging, as a complete pathophysiological understanding relies on accurate modeling and highly controlled variables. Genetically engineered mouse models are widely used to gain insight into the biology of human NDDs, but research focus has been on behavioral and neurophysiological abnormalities. Such models not only allow for evaluating usefulness in reproducing human features, including similarities and discrepancies with rodent phenotypes, but they also represent a unique opportunity to observe and quantify novel anomalies. Here, we present the first characterization and comparison of basal metabolism in three mouse models of NDDs, namely, Down syndrome (DS; Dp(16)Yey/+ mice), 16p11.2 deletion syndrome (16pDel; 16p11.2df/+ mice), and fragile X syndrome [FXS; Fmr1 knock-out (KO) mice] and their wild-type (WT) counterparts. Using the Comprehensive Lab Animal Monitoring System (CLAMS) coupled to EchoMRI, as well as quantification of key plasma metabolites by liquid chromatography mass spectrometry (LC-MS), our in vivo study reveals that each mouse model expresses a unique metabolic signature that is sex-specific, independent of the amount of food consumed and minimally influenced by physical activity. In particular, we identify striking differences in body composition, respiratory exchange ratio (RER), caloric expenditure (CE), and concentrations of circulating plasma metabolites related to mitochondrial function. Providing novel insight into NDD-associated metabolic alterations is an essential prerequisite for future preclinical and clinical interventions.
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Jain S, Watts CA, Chung WCJ, Welshhans K. Neurodevelopmental wiring deficits in the Ts65Dn mouse model of Down syndrome. Neurosci Lett 2020; 714:134569. [PMID: 31644920 DOI: 10.1016/j.neulet.2019.134569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 09/26/2019] [Accepted: 10/16/2019] [Indexed: 10/25/2022]
Abstract
Down syndrome is the most common genetic cause of intellectual disability and occurs due to the trisomy of human chromosome 21. Adolescent and adult brains from humans with Down syndrome exhibit various neurological phenotypes including a reduction in the size of the corpus callosum, hippocampal commissure and anterior commissure. However, it is unclear when and how these interhemispheric connectivity defects arise. Using the Ts65Dn mouse model of Down syndrome, we examined interhemispheric connectivity in postnatal day 0 (P0) Ts65Dn mouse brains. We find that there is no change in the volume of the corpus callosum or anterior commissure in P0 Ts65Dn mice. However, the volume of the hippocampal commissure is significantly reduced in P0 Ts65Dn mice, and this may contribute to the impaired learning and memory phenotype of this disorder. Interhemispheric connectivity defects that arise during development may be due to disrupted axon growth. In line with this, we find that developing hippocampal neurons display reduced axon length in vitro, as compared to neurons from their euploid littermates. This study is the first to report the presence of defective interhemispheric connectivity at the time of birth in Ts65Dn mice, providing evidence that early therapeutic intervention may be an effective time window for the treatment of Down syndrome.
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Affiliation(s)
- Shruti Jain
- Department of Biological Sciences, Kent State University, Kent, OH, 44242, USA
| | - Christina A Watts
- School of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA
| | - Wilson C J Chung
- Department of Biological Sciences, Kent State University, Kent, OH, 44242, USA; School of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA; Brain Health Research Institute, Kent State University, Kent, OH, 44242, USA
| | - Kristy Welshhans
- Department of Biological Sciences, Kent State University, Kent, OH, 44242, USA; School of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA; Brain Health Research Institute, Kent State University, Kent, OH, 44242, USA.
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Block A, Ahmed M, Rueda N, Hernandez MC, Martinez-Cué C, Gardiner K. The GABA A α5-selective Modulator, RO4938581, Rescues Protein Anomalies in the Ts65Dn Mouse Model of Down Syndrome. Neuroscience 2018; 372:192-212. [DOI: 10.1016/j.neuroscience.2017.12.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 12/19/2017] [Accepted: 12/21/2017] [Indexed: 12/21/2022]
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Roubertoux PL, Baril N, Cau P, Scajola C, Ghata A, Bartoli C, Bourgeois P, Christofaro JD, Tordjman S, Carlier M. Differential Brain, Cognitive and Motor Profiles Associated with Partial Trisomy. Modeling Down Syndrome in Mice. Behav Genet 2017; 47:305-322. [PMID: 28204906 DOI: 10.1007/s10519-017-9835-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 01/09/2017] [Indexed: 02/07/2023]
Abstract
We hypothesize that the trisomy 21 (Down syndrome) is the additive and interactive outcome of the triple copy of different regions of HSA21. Because of the small number of patients with partial trisomy 21, we addressed the question in the Mouse in which three chromosomal regions located on MMU10, MMU17 and MMU16 carries almost all the HSA21 homologs. Male mice from four segmental trisomic strains covering the D21S17-ETS2 (syntenic to MMU16) were examined with an exhaustive battery of cognitive tests, motor tasks and MRI and compared with TS65Dn that encompasses D21S17-ETS2. None of the four strains gather all the impairments (measured by the effect size) of TS65Dn strain. The 152F7 strain was close to TS65Dn for motor behavior and reference memory and the three other strains 230E8, 141G6 and 285E6 for working memory. Episodic memory was impaired only in strain 285E6. The hippocampus and cerebellum reduced sizes that were seen in all the strains indicate that trisomy 21 is not only a hippocampus syndrome but that it results from abnormal interactions between the two structures.
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Affiliation(s)
- Pierre L Roubertoux
- Aix Marseille University, INSERM, UMR_S 910, GMGF, TIMONE - 27 Boulevard Jean Moulin, 13005, Marseille, France.
| | - Nathalie Baril
- Department 3C, Aix Marseille University, CNRS, Marseille, France
| | - Pierre Cau
- Aix Marseille University, INSERM, UMR_S 910, GMGF, TIMONE - 27 Boulevard Jean Moulin, 13005, Marseille, France.,Department of Medical Genetics, AP-HM, Timone Hospital, Marseille, France.,Service de Biologie Cellulaire, AP-HM, Hôpital La Timone, 13385, Marseille Cedex 5, France
| | - Christophe Scajola
- Aix Marseille University, INSERM, UMR_S 910, GMGF, TIMONE - 27 Boulevard Jean Moulin, 13005, Marseille, France
| | - Adeline Ghata
- Aix Marseille University, INSERM, UMR_S 910, GMGF, TIMONE - 27 Boulevard Jean Moulin, 13005, Marseille, France
| | - Catherine Bartoli
- Aix Marseille University, INSERM, UMR_S 910, GMGF, TIMONE - 27 Boulevard Jean Moulin, 13005, Marseille, France
| | - Patrice Bourgeois
- Aix Marseille University, INSERM, UMR_S 910, GMGF, TIMONE - 27 Boulevard Jean Moulin, 13005, Marseille, France.,Department of Medical Genetics, AP-HM, Timone Hospital, Marseille, France
| | | | - Sylvie Tordjman
- Paris Descartes University, CNRS, LPP, Paris, France.,Rennes 1 University, PHUPEA, Rennes, France
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Mayfield J, Blednov YA, Harris RA. Behavioral and Genetic Evidence for GIRK Channels in the CNS: Role in Physiology, Pathophysiology, and Drug Addiction. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 123:279-313. [PMID: 26422988 DOI: 10.1016/bs.irn.2015.05.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
G protein-coupled inwardly rectifying potassium (GIRK) channels are widely expressed throughout the brain and mediate the inhibitory effects of many neurotransmitters. As a result, these channels are important for normal CNS function and have also been implicated in Down syndrome, Parkinson's disease, psychiatric disorders, epilepsy, and drug addiction. Knockout mouse models have provided extensive insight into the significance of GIRK channels under these conditions. This review examines the behavioral and genetic evidence from animal models and genetic association studies in humans linking GIRK channels with CNS disorders. We further explore the possibility that subunit-selective modulators and other advanced research tools will be instrumental in establishing the role of individual GIRK subunits in drug addiction and other relevant CNS diseases and in potentially advancing treatment options for these disorders.
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Affiliation(s)
- Jody Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas, USA.
| | - Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas, USA
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas, USA
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Chronic P7C3 treatment restores hippocampal neurogenesis in the Ts65Dn mouse model of Down Syndrome [Corrected]. Neurosci Lett 2015; 591:86-92. [PMID: 25668489 DOI: 10.1016/j.neulet.2015.02.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/20/2015] [Accepted: 02/06/2015] [Indexed: 12/11/2022]
Abstract
Down syndrome (DS) is the most common genetic cause of intellectual disability and developmental delay. In addition to cognitive dysfunction, DS patients are marked by diminished neurogenesis, a neuropathological feature also found in the Ts65Dn mouse model of DS. Interestingly, manipulations that enhance neurogenesis - like environmental enrichment or pharmacological agents - improve cognition in Ts65Dn mice. P7C3 is a proneurogenic compound that enhances hippocampal neurogenesis, cell survival, and promotes cognition in aged animals. However, this compound has not been tested in the Ts65Dn mouse model of DS. We hypothesized that P7C3 treatment would reverse or ameliorate the neurogenic deficits in Ts65Dn mice. To test this, adult Ts65Dn and age-matched wild-type (WT) mice were administered vehicle or P7C3 twice daily for 3 months. After 3 months, brains were examined for indices of neurogenesis, including quantification of Ki67, DCX, activated caspase-3 (AC3), and surviving BrdU-immunoreactive(+) cells in the granule cell layer (GCL) of the hippocampal dentate gyrus. P7C3 had no effect on total Ki67+, DCX+, AC3+, or surviving BrdU+ cells in WT mice relative to vehicle. GCL volume was also not changed. In keeping with our hypothesis, however, P7C3-treated Ts65Dn mice had a significant increase in total Ki67+, DCX+, and surviving BrdU+ cells relative to vehicle. P7C3 treatment also decreased AC3+ cell number but had no effect on total GCL volume in Ts65Dn mice. Our findings show 3 months of P7C3 is sufficient to restore the neurogenic deficits observed in the Ts65Dn mouse model of DS.
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Gardiner KJ. Pharmacological approaches to improving cognitive function in Down syndrome: current status and considerations. Drug Des Devel Ther 2014; 9:103-25. [PMID: 25552901 PMCID: PMC4277121 DOI: 10.2147/dddt.s51476] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Down syndrome (DS), also known as trisomy 21, is the most common genetic cause of intellectual disability (ID). Although ID can be mild, the average intelligence quotient is in the range of 40-50. All individuals with DS will also develop the neuropathology of Alzheimer's disease (AD) by the age of 30-40 years, and approximately half will display an AD-like dementia by the age of 60 years. DS is caused by an extra copy of the long arm of human chromosome 21 (Hsa21) and the consequent elevated levels of expression, due to dosage, of trisomic genes. Despite a worldwide incidence of one in 700-1,000 live births, there are currently no pharmacological treatments available for ID or AD in DS. However, over the last several years, very promising results have been obtained with a mouse model of DS, the Ts65Dn. A diverse array of drugs has been shown to rescue, or partially rescue, DS-relevant deficits in learning and memory and abnormalities in cellular and electrophysiological features seen in the Ts65Dn. These results suggest that some level of amelioration or prevention of cognitive deficits in people with DS may be possible. Here, we review information from the preclinical evaluations in the Ts65Dn, how drugs were selected, how efficacy was judged, and how outcomes differ, or not, among studies. We also summarize the current state of human clinical trials for ID and AD in DS. Lastly, we describe the genetic limitations of the Ts65Dn as a model of DS, and in the preclinical testing of pharmacotherapeutics, and suggest additional targets to be considered for potential pharmacotherapies.
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Affiliation(s)
- Katheleen J Gardiner
- Linda Crnic Institute for Down Syndrome, Department of Pediatrics, Department of Biochemistry and Molecular Genetics, Human Medical Genetics and Genomics Program, Neuroscience Program, University of Colorado School of Medicine, Aurora, CO, USA
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Evidence of altered age-related brain cytoarchitecture in mouse models of down syndrome: a diffusional kurtosis imaging study. Magn Reson Imaging 2014; 33:437-47. [PMID: 25527393 DOI: 10.1016/j.mri.2014.12.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/26/2014] [Accepted: 12/01/2014] [Indexed: 11/22/2022]
Abstract
Mouse models of Down syndrome (DS) exhibit abnormal brain developmental and neurodegenerative changes similar to those seen in individuals with DS. Although DS mice have been well characterized cognitively and morphologically there are no prior reports utilizing diffusion MRI. In this study we investigated the ability of diffusional kurtosis imaging (DKI) to detect the progressive developmental and neurodegenerative changes in the Ts65Dn (TS) DS mouse model. TS mice displayed higher diffusional kurtosis (DK) in the frontal cortex (FC) compared to normal mice at 2months of age. At 5months of age, TS mice had lower radial kurtosis in the striatum (ST), which persisted in the 8-month-old mice. The TS mice exhibited lower DK metrics values in the dorsal hippocampus (HD) at all ages, and the group difference in this region was larger at 8-months. Regression analysis showed that normal mice had a significant age-related increase in DK metrics in FC, ST and HD. On the contrary, the TS mice lacked significant age-related increase in DK metrics in FC and ST. Although preliminary, these results demonstrate that DK metrics can detect TS brain developmental and neurodegenerative abnormalities.
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Enea-Drapeau C, Huguet P, Carlier M. Misleading face-based judgment of cognitive level in intellectual disability: the case of trisomy 21 (Down syndrome). RESEARCH IN DEVELOPMENTAL DISABILITIES 2014; 35:3598-3605. [PMID: 25244694 DOI: 10.1016/j.ridd.2014.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/29/2014] [Accepted: 09/02/2014] [Indexed: 06/03/2023]
Abstract
People spontaneously use faces to make inferences about other's personality traits or abilities, which generally lead to invalid conclusions. Here, we show first evidence that perceived variations in the facial appearance of 20 children with trisomy 21 (t21) influence how they are perceived in terms of intelligence (or intellectual disability), the more "trisomic" faces being rated as less intelligent (or more intellectually disabled). Despite high degrees of inter-rater agreement (80 raters), these inferences were unrelated to individuals' actual test scores which were also unrelated to perceived facial appearance. All these findings indicate that social inferences about intelligence based on facial appearance are unreliable even in groups characterized by a genetic disorder such as t21.
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Affiliation(s)
- Claire Enea-Drapeau
- Aix Marseille Université, CNRS, LPC UMR 7290, Fédération de recherche 3C, 13331 Marseille, France.
| | - Pascal Huguet
- Aix Marseille Université, CNRS, LPC UMR 7290, Fédération de recherche 3C, 13331 Marseille, France.
| | - Michèle Carlier
- Aix Marseille Université, CNRS, LPC UMR 7290, Fédération de recherche 3C, 13331 Marseille, France.
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Hernández-González S, Ballestín R, López-Hidalgo R, Gilabert-Juan J, Blasco-Ibáñez JM, Crespo C, Nácher J, Varea E. Altered distribution of hippocampal interneurons in the murine Down Syndrome model Ts65Dn. Neurochem Res 2014; 40:151-64. [PMID: 25399236 DOI: 10.1007/s11064-014-1479-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/10/2014] [Accepted: 11/12/2014] [Indexed: 12/30/2022]
Abstract
Down Syndrome, with an incidence of one in 800 live births, is the most common genetic alteration producing intellectual disability. We have used the Ts65Dn model, that mimics some of the alterations observed in Down Syndrome. This genetic alteration induces an imbalance between excitation and inhibition that has been suggested as responsible for the cognitive impairment present in this syndrome. The hippocampus has a crucial role in memory processing and is an important area to analyze this imbalance. In this report we have analysed, in the hippocampus of Ts65Dn mice, the expression of synaptic markers: synaptophysin, vesicular glutamate transporter-1 and isoform 67 of the glutamic acid decarboxylase; and of different subtypes of inhibitory neurons (Calbindin D-28k, parvalbumin, calretinin, NPY, CCK, VIP and somatostatin). We have observed alterations in the inhibitory neuropil in the hippocampus of Ts65Dn mice. There was an excess of inhibitory puncta and a reduction of the excitatory ones. In agreement with this observation, we have observed an increase in the number of inhibitory neurons in CA1 and CA3, mainly interneurons expressing calbindin, calretinin, NPY and VIP, whereas parvalbumin cell numbers were not affected. These alterations in the number of interneurons, but especially the alterations in the proportion of the different types, may influence the normal function of inhibitory circuits and underlie the cognitive deficits observed in DS.
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Affiliation(s)
- Samuel Hernández-González
- Neurobiology Unit, Program in Basic and Applied Neurosciences, Cell Biology Department, Universitat de València, Dr. Moliner, 50, 46100, Burjassot, Spain
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Pipino C, Mukherjee S, David AL, Blundell MP, Shaw SW, Sung P, Shangaris P, Waters JJ, Ellershaw D, Cavazzana M, Mostoslavsky G, Pandolfi A, Pierro A, Guillot PV, Thrasher AJ, De Coppi P. Trisomy 21 mid-trimester amniotic fluid induced pluripotent stem cells maintain genetic signatures during reprogramming: implications for disease modeling and cryobanking. Cell Reprogram 2014; 16:331-44. [PMID: 25162836 DOI: 10.1089/cell.2013.0091] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Trisomy 21 is the most common chromosomal abnormality and is associated primarily with cardiovascular, hematological, and neurological complications. A robust patient-derived cellular model is necessary to investigate the pathophysiology of the syndrome because current animal models are limited and access to tissues from affected individuals is ethically challenging. We aimed to derive induced pluripotent stem cells (iPSCs) from trisomy 21 human mid-trimester amniotic fluid stem cells (AFSCs) and describe their hematopoietic and neurological characteristics. Human AFSCs collected from women undergoing prenatal diagnosis were selected for c-KIT(+) and transduced with a Cre-lox-inducible polycistronic lentiviral vector encoding SOX2, OCT4, KLF-4, and c-MYC (50,000 cells at a multiplicity of infection (MOI) 1-5 for 72 h). The embryonic stem cell (ESC)-like properties of the AFSC-derived iPSCs were established in vitro by embryoid body formation and in vivo by teratoma formation in RAG2(-/-), γ-chain(-/-), C2(-/-) immunodeficient mice. Reprogrammed cells retained their cytogenetic signatures and differentiated into specialized hematopoietic and neural precursors detected by morphological assessment, immunostaining, and RT-PCR. Additionally, the iPSCs expressed all pluripotency markers upon multiple rounds of freeze-thawing. These findings are important in establishing a patient-specific cellular platform of trisomy 21 to study the pathophysiology of the aneuploidy and for future drug discovery.
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Affiliation(s)
- Caterina Pipino
- 1 Surgery Unit, Institute of Child Health, University College London , London, WC1N 1EH, United Kingdom
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Engineered chromosome-based genetic mapping establishes a 3.7 Mb critical genomic region for Down syndrome-associated heart defects in mice. Hum Genet 2013; 133:743-53. [PMID: 24362460 DOI: 10.1007/s00439-013-1407-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 12/06/2013] [Indexed: 02/01/2023]
Abstract
Trisomy 21 (Down syndrome, DS) is the most common human genetic anomaly associated with heart defects. Based on evolutionary conservation, DS-associated heart defects have been modeled in mice. By generating and analyzing mouse mutants carrying different genomic rearrangements in human chromosome 21 (Hsa21) syntenic regions, we found the triplication of the Tiam1-Kcnj6 region on mouse chromosome 16 (Mmu16) resulted in DS-related cardiovascular abnormalities. In this study, we developed two tandem duplications spanning the Tiam1-Kcnj6 genomic region on Mmu16 using recombinase-mediated genome engineering, Dp(16)3Yey and Dp(16)4Yey, spanning the 2.1 Mb Tiam1-Il10rb and 3.7 Mb Ifnar1-Kcnj6 regions, respectively. We found that Dp(16)4Yey/+, but not Dp(16)3Yey/+, led to heart defects, suggesting the triplication of the Ifnar1-Kcnj6 region is sufficient to cause DS-associated heart defects. Our transcriptional analysis of Dp(16)4Yey/+ embryos showed that the Hsa21 gene orthologs located within the duplicated interval were expressed at the elevated levels, reflecting the consequences of the gene dosage alterations. Therefore, we have identified a 3.7 Mb genomic region, the smallest critical genomic region, for DS-associated heart defects, and our results should set the stage for the final step to establish the identities of the causal gene(s), whose elevated expression(s) directly underlie this major DS phenotype.
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Millan MJ. An epigenetic framework for neurodevelopmental disorders: from pathogenesis to potential therapy. Neuropharmacology 2012; 68:2-82. [PMID: 23246909 DOI: 10.1016/j.neuropharm.2012.11.015] [Citation(s) in RCA: 150] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 11/11/2012] [Accepted: 11/22/2012] [Indexed: 12/12/2022]
Abstract
Neurodevelopmental disorders (NDDs) are characterized by aberrant and delayed early-life development of the brain, leading to deficits in language, cognition, motor behaviour and other functional domains, often accompanied by somatic symptoms. Environmental factors like perinatal infection, malnutrition and trauma can increase the risk of the heterogeneous, multifactorial and polygenic disorders, autism and schizophrenia. Conversely, discrete genetic anomalies are involved in Down, Rett and Fragile X syndromes, tuberous sclerosis and neurofibromatosis, the less familiar Phelan-McDermid, Sotos, Kleefstra, Coffin-Lowry and "ATRX" syndromes, and the disorders of imprinting, Angelman and Prader-Willi syndromes. NDDs have been termed "synaptopathies" in reference to structural and functional disturbance of synaptic plasticity, several involve abnormal Ras-Kinase signalling ("rasopathies"), and many are characterized by disrupted cerebral connectivity and an imbalance between excitatory and inhibitory transmission. However, at a different level of integration, NDDs are accompanied by aberrant "epigenetic" regulation of processes critical for normal and orderly development of the brain. Epigenetics refers to potentially-heritable (by mitosis and/or meiosis) mechanisms controlling gene expression without changes in DNA sequence. In certain NDDs, prototypical epigenetic processes of DNA methylation and covalent histone marking are impacted. Conversely, others involve anomalies in chromatin-modelling, mRNA splicing/editing, mRNA translation, ribosome biogenesis and/or the regulatory actions of small nucleolar RNAs and micro-RNAs. Since epigenetic mechanisms are modifiable, this raises the hope of novel therapy, though questions remain concerning efficacy and safety. The above issues are critically surveyed in this review, which advocates a broad-based epigenetic framework for understanding and ultimately treating a diverse assemblage of NDDs ("epigenopathies") lying at the interface of genetic, developmental and environmental processes. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.
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Affiliation(s)
- Mark J Millan
- Unit for Research and Discovery in Neuroscience, IDR Servier, 125 chemin de ronde, 78290 Croissy sur Seine, Paris, France.
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Spellman C, Ahmed MM, Dubach D, Gardiner KJ. Expression of trisomic proteins in Down syndrome model systems. Gene 2012; 512:219-25. [PMID: 23103828 DOI: 10.1016/j.gene.2012.10.051] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 09/06/2012] [Accepted: 10/09/2012] [Indexed: 12/21/2022]
Abstract
Down syndrome (DS) is the most common genetic aberration leading to intellectual disability. DS results from an extra copy of the long arm of human chromosome 21 (HSA21) and the increased expression of trisomic genes due to gene dosage. While expression in DS and DS models has been studied extensively at the RNA level, much less is known about expression of trisomic genes at the protein level. We have used quantitative Western blotting with antibodies to 20 proteins encoded by HSA21 to assess trisomic protein expression in lymphoblastoid cell lines (LCLs) from patients with DS and in brains from two mouse models of DS. These antibodies have recently become available and the 20 proteins largely have not been investigated previously for their potential contributions to the phenotypic features of DS. Twelve proteins had detectable expression in LCLs and three, CCT8, MX1 and PWP2, showed elevated levels in LCLs derived from patients with DS compared with controls. Antibodies against 15 proteins detected bands of appropriate sizes in lysates from mouse brain cortex. Genes for 12 of these proteins are trisomic in the Tc1 mouse model of DS, but only SIM2 and ZNF295 showed elevated expression in Tc1 cortex when compared with controls. Genes for eight of the 15 proteins are trisomic in the Ts65Dn mouse model of DS, but only ZNF294 was over expressed in cortex. Comparison of trisomic gene expression at the protein level with previous reports at the mRNA level showed many inconsistencies. These may be caused by natural inter-individual variability, differences in the age of mice analyzed, or post-transcriptional regulation of gene dosage effects. These antibodies provide resources for further investigation of the molecular basis of intellectual disability in DS.
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Affiliation(s)
- Claire Spellman
- Department of Pediatrics, Linda Crnic Institute for Down Syndrome, Intellectual and Developmental Disabilities Research Center, University of Colorado Denver School of Medicine, 12700 E 19th Avenue, Mail Stop 8608, Aurora, CO 80045, USA.
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Dental approach to craniofacial syndromes: how can developmental fields show us a new way to understand pathogenesis? Int J Dent 2012; 2012:145749. [PMID: 23091490 PMCID: PMC3467949 DOI: 10.1155/2012/145749] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 07/10/2012] [Accepted: 07/25/2012] [Indexed: 12/19/2022] Open
Abstract
The paper consists of three parts. Part 1: Definition of Syndromes. Focus is given to craniofacial syndromes in which abnormal traits in the dentition are associated symptoms. In the last decade, research has concentrated on phenotype, genotype, growth, development, function, and treatment. Part 2: Syndromes before Birth. How can the initial malformation sites in these syndromes be studied and what can we learn from it? In this section, deviations observed in syndromes prenatally will be highlighted and compared to the normal human embryological craniofacial development. Specific focus will be given to developmental fields studied on animal tissue and transferred to human cranial development. Part 3: Developmental Fields Affected in Two Craniofacial Syndromes. Analysis of primary and permanent dentitions can determine whether a syndrome affects a single craniofacial field or several fields. This distinction is essential for insight into craniofacial syndromes. The dentition, thus, becomes central in diagnostics and evaluation of the pathogenesis. Developmental fields can explore and advance the concept of dental approaches to craniofacial syndromes. Discussion. As deviations in teeth persist and do not reorganize during growth and development, the dentition is considered useful for distinguishing between syndrome pathogenesis manifested in a single developmental field and in several fields.
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Human and mouse model cognitive phenotypes in Down syndrome: implications for assessment. PROGRESS IN BRAIN RESEARCH 2012; 197:123-51. [PMID: 22541291 DOI: 10.1016/b978-0-444-54299-1.00007-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The study of cognitive function in Down syndrome (DS) has advanced rapidly in the past decade. Mouse models have generated data regarding the neurological basis for the specific cognitive profile of DS (i.e., deficits in aspects of hippocampal, prefrontal, and cerebellar function) and have uncovered pharmacological treatments with the potential to affect this phenotype. Given this progress, the field is at a juncture in which we require assessments that may effectively translate the findings acquired in mouse models to humans with DS. In this chapter, we describe the cognitive profile of humans with DS and associated mouse models, discussing the ways in which we may merge these findings so as to more fully understand cognitive strengths and weaknesses in this population. New directions for approaches to cognitive assessment in mice and humans are discussed.
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Ogawa Y, Hagiwara M. Challenges to congenital genetic disorders with “RNA-targeting” chemical compounds. Pharmacol Ther 2012; 134:298-305. [DOI: 10.1016/j.pharmthera.2012.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 01/24/2012] [Indexed: 11/16/2022]
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Trisomy of the G protein-coupled K+ channel gene, Kcnj6, affects reward mechanisms, cognitive functions, and synaptic plasticity in mice. Proc Natl Acad Sci U S A 2012; 109:2642-7. [PMID: 22308328 DOI: 10.1073/pnas.1109099109] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
G protein-activated inwardly rectifying K+ channels (GIRK) generate slow inhibitory postsynaptic potentials in the brain via G(i/o) protein-coupled receptors. GIRK2, a GIRK subunit, is widely abundant in the brain and has been implicated in various functions and pathologies, such as learning and memory, reward, motor coordination, and Down syndrome. Down syndrome, the most prevalent cause of mental retardation, results from the presence of an extra maternal chromosome 21 (trisomy 21), which comprises the Kcnj6 gene (GIRK2). The present study examined the behaviors and cellular physiology properties in mice harboring a single trisomy of the Kcnj6 gene. Kcnj6 triploid mice exhibit deficits in hippocampal-dependent learning and memory, altered responses to rewards, hampered depotentiation, a form of excitatory synaptic plasticity, and have accentuated long-term synaptic depression. Collectively the findings suggest that triplication of Kcnj6 gene may play an active role in some of the abnormal neurological phenotypes found in Down syndrome.
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Régnier V, Billard JM, Gupta S, Potier B, Woerner S, Paly E, Ledru A, David S, Luilier S, Bizot JC, Vacano G, Kraus JP, Patterson D, Kruger WD, Delabar JM, London J. Brain phenotype of transgenic mice overexpressing cystathionine β-synthase. PLoS One 2012; 7:e29056. [PMID: 22253703 PMCID: PMC3257219 DOI: 10.1371/journal.pone.0029056] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 11/20/2011] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The cystathionine β-synthase (CBS) gene, located on human chromosome 21q22.3, is a good candidate for playing a role in the Down Syndrome (DS) cognitive profile: it is overexpressed in the brain of individuals with DS, and it encodes a key enzyme of sulfur-containing amino acid (SAA) metabolism, a pathway important for several brain physiological processes. METHODOLOGY/PRINCIPAL FINDINGS Here, we have studied the neural consequences of CBS overexpression in a transgenic mouse line (60.4P102D1) expressing the human CBS gene under the control of its endogenous regulatory regions. These mice displayed a ∼2-fold increase in total CBS proteins in different brain areas and a ∼1.3-fold increase in CBS activity in the cerebellum and the hippocampus. No major disturbance of SAA metabolism was observed, and the transgenic mice showed normal behavior in the rotarod and passive avoidance tests. However, we found that hippocampal synaptic plasticity is facilitated in the 60.4P102D1 line. CONCLUSION/SIGNIFICANCE We demonstrate that CBS overexpression has functional consequences on hippocampal neuronal networks. These results shed new light on the function of the CBS gene, and raise the interesting possibility that CBS overexpression might have an advantageous effect on some cognitive functions in DS.
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Affiliation(s)
- Vinciane Régnier
- Unité de Biologie Fonctionnelle et Adaptative, CNRS EAC 4413, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
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20
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Sturgeon X, Le T, Ahmed MM, Gardiner KJ. Pathways to cognitive deficits in Down syndrome. PROGRESS IN BRAIN RESEARCH 2012; 197:73-100. [PMID: 22541289 DOI: 10.1016/b978-0-444-54299-1.00005-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Major efforts in Down syndrome (DS) research have been directed at the identification and functional characterization of genes encoded by human chromosome 21 (HSA21). In parallel with this, tissue samples and cell lines derived from individuals with DS have been examined for abnormalities in gene expression and cellular morphology, and mouse models of DS have been characterized for abnormalities at the molecular, cellular, electrophysiological, and behavioral level. One goal of such investigations has been the identification of effective targets for pharmacotherapies that can prevent or correct the abnormalities and, by extension to human clinical trials, prevent or lessen aspects of the cognitive deficits seen in people with DS. Because it is caused by an extra copy of an entire chromosome, DS has been considered by some as too complicated a genetic perturbation to be amenable to postnatal pharmacological interventions. However, recent data from experiments with one mouse model, the Ts65Dn, have clearly demonstrated that several pharmacological interventions can indeed rescue DS-relevant learning and memory deficits. Extension of mouse data to successful human clinical trials will be aided by understanding the molecular basis of successful drug treatments, that is, how increased expression of HSA21 genes perturbs molecular mechanisms that are targeted and rescued by specific drugs. Here, we review information on HSA21 genes, their expression and their likely contributions to the DS phenotype. We then describe results of a bioinformatics effort that integrates information on genes known to cause intellectual disability when mutated, the pathways in which these genes function, and how these pathways are impacted by HSA21 encoded proteins. This pathway approach to the molecular basis of ID in DS aids in understanding why some drug therapies have been successful in the Ts65Dn and in predicting whether these same drugs are likely to be successful in treating ID in DS. These data can be used to design new experiments and interpret information for prediction of additional targets for effective drug treatments.
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Affiliation(s)
- Xiaolu Sturgeon
- Department of Pediatrics, University of Colorado Denver, Denver, CO, USA
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21
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Lott IT. Antioxidants in Down syndrome. Biochim Biophys Acta Mol Basis Dis 2011; 1822:657-63. [PMID: 22206998 DOI: 10.1016/j.bbadis.2011.12.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 12/13/2011] [Accepted: 12/14/2011] [Indexed: 01/09/2023]
Abstract
Individuals with Down syndrome (DS) have high levels of oxidative stress throughout the lifespan. Mouse models of DS share some structural and functional abnormalities that parallel findings seen in the human phenotype. Several of the mouse models show evidence of cellular oxidative stress and have provided a platform for antioxidant intervention. Genes that are overexpressed on chromosome 21 are associated with oxidative stress and neuronal apoptosis. The lack of balance in the metabolism of free radicals generated during processes related to oxidative stress may have a direct role in producing the neuropathology of DS including the tendency to Alzheimer disease (AD). Mitochondria are often a target for oxidative stress and are considered to be a trigger for the onset of the AD process in DS. Biomarkers for oxidative stress have been described in DS and in AD in the general population. However, intervention trials using standard antioxidant supplements or diets have failed to produce uniform therapeutic effect. This chapter will examine the biological role of oxidative stress in DS and its relationship to abnormalities in both development and aging within the disorder. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.
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Affiliation(s)
- Ira T Lott
- Department of Pediatrics and Neurology, School of Medicine, University of California Irvine (UCI), Orange, CA 92868, USA.
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Gotti S, Caricati E, Panzica G. Alterations of brain circuits in Down syndrome murine models. J Chem Neuroanat 2011; 42:317-26. [DOI: 10.1016/j.jchemneu.2011.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 09/04/2011] [Accepted: 09/06/2011] [Indexed: 10/17/2022]
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Liu C, Belichenko PV, Zhang L, Fu D, Kleschevnikov AM, Baldini A, Antonarakis SE, Mobley WC, Yu YE. Mouse models for Down syndrome-associated developmental cognitive disabilities. Dev Neurosci 2011; 33:404-13. [PMID: 21865664 DOI: 10.1159/000329422] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 03/23/2011] [Indexed: 12/19/2022] Open
Abstract
Down syndrome (DS) is mainly caused by the presence of an extra copy of human chromosome 21 (Hsa21) and is a leading genetic cause for developmental cognitive disabilities in humans. The mouse is a premier model organism for DS because the regions on Hsa21 are syntenically conserved with three regions in the mouse genome, which are located on mouse chromosome 10 (Mmu10), Mmu16 and Mmu17. With the advance of chromosomal manipulation technologies, new mouse mutants have been generated to mimic DS at both the genotypic and phenotypic levels. Further mouse-based molecular genetic studies in the future may lead to the unraveling of the mechanisms underlying DS-associated developmental cognitive disabilities, which would lay the groundwork for developing effective treatments for this phenotypic manifestation. In this review, we will discuss recent progress and future challenges in modeling DS-associated developmental cognitive disability in mice with an emphasis on hippocampus-related phenotypes.
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Affiliation(s)
- Chunhong Liu
- Children's Guild Foundation Down Syndrome Research Program and Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
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Roubertoux PL, de Vries PJ. From molecules to behavior: lessons from the study of rare genetic disorders. Behav Genet 2011; 41:341-8. [PMID: 21541644 DOI: 10.1007/s10519-011-9469-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 04/19/2011] [Indexed: 10/18/2022]
Abstract
Rare diseases are defined as conditions with a prevalence of less than 1/2,000. To date between 6,000 and 7,000 rare diseases have been identified and many of those have manifestations that include intellectual disability, developmental disorders or other behavioural phenotypes. In this special issue we bring together a range of papers where rare diseases were used as models to delineate specific aspects of learning and memory, or behaviour. In this introductory paper we summarize some of the lessons we can learn from rare diseases. Firstly, we learn that, collectively, rare diseases are not at all rare. As many as 1 in 20 individuals may be affected by a rare disease at some point in their life. Secondly, we learn that rare diseases may share common pathophysiological mechanisms. A discovery in one can therefore have direct relevance to many others. A third lesson is that the study of rare diseases can lead to an understanding of common disorders, as exemplified by the relationship between Trisomy 21 (Down syndrome) and Alzheimer's disease. A fourth lesson from rare diseases is that the 'one gene-one functional consequence' assumption is not correct. Finally, rare diseases have shed new light on the strengths and weaknesses of animal models in the study of behavioural phenotypes.
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Affiliation(s)
- Pierre L Roubertoux
- Génétique Médicale, Génomique Fonctionnelle, Aix Marseille Université, Marseille cedex, France
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