Dataset Information

Molecular responses of the Ts65Dn and Ts1Cje mouse models of Down syndrome to MK-801.

ABSTRACT: Down syndrome (DS), caused by trisomy of human chromosome 21 (chr21), is the most common genetic cause of intellectual disability. The Ts65Dn mouse model of DS is trisomic for orthologs of 94 chr21-encoded, confirmed protein-coding genes and displays a number of behavioral deficits. Recently, Ts65Dn mice were shown to be hypersensitive to the locomotor stimulatory effects of the high-affinity N-methyl-d-aspartate (NMDA) receptor (NMDAR) channel blocker, MK-801. This is consistent with the functions of several chr21 proteins that are predicted directly or indirectly to impact NMDAR function or NMDAR-mediated signaling. In this study, we show that a second mouse model of DS, the Ts1Cje, which is trisomic for 70 protein-coding genes, is also hypersensitive to MK-801. To investigate the molecular basis for the responses to MK-801, we have measured levels of a subset of chr21 and phosphorylated non-chr21 proteins, in the cortex and hippocampus of Ts65Dn and Ts1Cje mice and euploid controls, with and without treatment with MK-801. We show that in euploid mice, the chr21-encoded proteins, TIAM1 and DYRK1A, and phosphorylation of AKT, ERK1/2 and the transcription factor ELK are involved in the MK-801 response. However, in both Ts65Dn and Ts1Cje mice, levels of phosphorylation are constitutively elevated in naïve, unstimulated mice, and the MK-801-induced changes in TIAM1 and DYRK1A and in phosphorylation are either absent or abnormal, with both genotype and brain-region-specific patterns. These results emphasize the complexities of the pathway perturbations that arise with segmental trisomy.

SUBMITTER: Siddiqui A

PROVIDER: S-EPMC2677016 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Molecular responses of the Ts65Dn and Ts1Cje mouse models of Down syndrome to MK-801.

Siddiqui A A Lacroix T T Stasko M R MR Scott-McKean J J JJ Costa A C S AC Gardiner K J KJ

Genes, brain, and behavior 20081001 7

Down syndrome (DS), caused by trisomy of human chromosome 21 (chr21), is the most common genetic cause of intellectual disability. The Ts65Dn mouse model of DS is trisomic for orthologs of 94 chr21-encoded, confirmed protein-coding genes and displays a number of behavioral deficits. Recently, Ts65Dn mice were shown to be hypersensitive to the locomotor stimulatory effects of the high-affinity N-methyl-d-aspartate (NMDA) receptor (NMDAR) channel blocker, MK-801. This is consistent with the functi ...[more]

PMID: 19125866

Similar Datasets

Project description:Down syndrome (DS) results from triplication of human chromosome 21. Neuropathological hallmarks of DS include atypical central nervous system development that manifests prenatally and extends throughout life. As a result, individuals with DS exhibit cognitive and motor deficits, and have delays in achieving developmental milestones. To determine whether different mouse models of DS recapitulate the human prenatal and postnatal phenotypes, here, we directly compared brain histogenesis, gene expression and behavior over the lifespan of three cytogenetically distinct mouse models of DS: Ts1Cje, Ts65Dn and Dp(16)1/Yey. Histological data indicated that Ts65Dn mice were the most consistently affected with respect to somatic growth, neurogenesis and brain morphogenesis. Embryonic and adult gene expression results showed that Ts1Cje and Ts65Dn brains had considerably more differentially expressed (DEX) genes compared with Dp(16)1/Yey mice, despite the larger number of triplicated genes in the latter model. In addition, DEX genes showed little overlap in identity and chromosomal distribution in the three models, leading to dissimilarities in affected functional pathways. Perinatal and adult behavioral testing also highlighted differences among the models in their abilities to achieve various developmental milestones and perform hippocampal- and motor-based tasks. Interestingly, Dp(16)1/Yey mice showed no abnormalities in prenatal brain phenotypes, yet they manifested behavioral deficits starting at postnatal day 15 that continued through adulthood. In contrast, Ts1Cje mice showed mildly abnormal embryonic brain phenotypes, but only select behavioral deficits as neonates and adults. Altogether, our data showed widespread and unexpected fundamental differences in behavioral, gene expression and brain development phenotypes between these three mouse models. Our findings illustrate unique limitations of each model when studying aspects of brain development and function in DS. This work helps to inform model selection in future studies investigating how observed neurodevelopmental abnormalities arise, how they contribute to cognitive impairment, and when testing therapeutic molecules to ameliorate the intellectual disability associated with DS.This article has an associated First Person interview with the first author of the paper.

Project description:Down syndrome (DS), a genetic condition leading to intellectual disability, is characterized by triplication of human chromosome 21. Neuropathological hallmarks of DS include abnormal central nervous system development that manifests during gestation and extends throughout life. As a result, newborns and adults with DS exhibit cognitive and motor deficits and fail to meet typical developmental and lack independent life skills. A critical outstanding question is how DS-specific prenatal and postnatal phenotypes are recapitulated in different mouse models. To begin answering this question, we developed a life span approach to directly compare differences in embryonic brain development, cellularity, gene expression, neonatal and adult behavior behavior in three cytogenetically distinct mouse models of DS—Ts1Cje, Ts65Dn and Dp16/1Yey (Dp16). In the last two decades multiple therapeutic trials have been attempted to improve cognition in humans with DS but the results of these interventions lacked efficacy despide their succes in the Ts65Dn mouse model of DS. To better understand how phenotypic changes in humans in DS are recapitulated in different mouse models, we copared embryonic brain development and gene expression, perinatal behavior and brain excitatoty/inhibitory cell distribution, and adult behavior and gene expression in the Dp16, Ts65Dn and Ts1Cje mouse models of DS. The objectives of this study were to determine the best model(s) for prenatal and postnatal therapeutic trials and to identify treatment endpoints that can be used to evaluate the fficacy of these therapies prior to human clinical trials. Our data showed that, at embryonic day 15.5, Ts65Dn mice are the most profoundly and consistently affected with respect to somatic growth, brain morphogenesis, and neurogenesis compared to Ts1Cje and Dp16 embryos. However, gene expression results show that both Ts65Dn and Ts1Cje embryonic forebrains have a relatively high number of differentially expressed genes compared to Dp16, with little overlap in gene identities and genomic distribution observed among these models. Additionally, postnatal histological analyses show varying degrees of cell population and brain histogenesis abnormalities among the three strains. Behavioral testing also highlights differences among the models in their ability to meet various developmental milestones. At adulthood, Ts65Dn and Ts1Cje showed hyperactive behavior in the open field test but not Dp16 mice. In the fear conditioning test, all three strains showed lower freezing versus eupploid mice; Dp16 were the most severely affected. In the Morris water maze, Ts65Dn showed significant delays in the hidden platform, probe and reversal trials. Dp16 mice showed milder deficits in the hidden platform trial but severe deficits in reversal. Ts1Cje mice had no spatial memory deficits. In the rotarod test, Dp16 performed poorly in fixed and accelerating speed trials, while Ts1Cje was only abnormal at high speeds. Ts65Dn rotarod performance was unaffected. Compared to euploid, Ts65Dn had a higher number of differentially expressed (DEX) genes in cortex and cerebellum, while Ts1Cje had more DEX genes in hippocampus and cerebellum. Dp16 had the lowest number of DEX genes in all regions analyzed. Pathway analyses highlighted commonly dysregulated pathways, including G-protein signaling, oxidative stress, interferon signaling, glycosylation and disulfide bonds.

Dataset Information

Molecular responses of the Ts65Dn and Ts1Cje mouse models of Down syndrome to MK-801.

Publications

Molecular responses of the Ts65Dn and Ts1Cje mouse models of Down syndrome to MK-801.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets