Neurodevelopmental delay, motor abnormalities and cognitive deficits in transgenic mice overexpressing DYRK1a (minibrain), a murine model of Down's syndrome. Hum Mol Genet

Department of Physiology and Pharmacology, Universidad de Cantabria, Santander, Cantabria, Spain
Human Molecular Genetics (Impact Factor: 6.39). 10/2001; 10(18):1915-23. DOI: 10.1093/hmg/10.18.1915
Source: PubMed


Down's syndrome (DS) is a major cause of mental retardation, hypotonia and delayed development. Murine models of DS carrying large murine or human genomic fragments show motor alterations and memory deficits. The specific genes responsible for these phenotypic alterations have not yet been defined. DYRK1A, the human homolog of the Drosophila minibrain gene, maps to the DS critical region of human chromosome 21 and is overexpressed in DS fetal brain. DYRK1A encodes a serine-threonine kinase, probably involved in neuroblast proliferation. Mutant Drosophila minibrain flies have a reduction in both optic lobes and central brain, showing learning deficits and hypoactivity. We have generated transgenic mice (TgDyrk1A) overexpressing the full-length cDNA of Dyrk1A. TgDyrk1A mice exhibit delayed cranio-caudal maturation with functional consequences in neuromotor development. TgDyrk1A mice also show altered motor skill acquisition and hyperactivity, which is maintained to adulthood. In the Morris water maze, TgDyrk1A mice show a significant impairment in spatial learning and cognitive flexibility, indicative of hippocampal and prefrontal cortex dysfunction. In the more complex repeated reversal learning paradigm, this defect turned out to be specifically related to reference memory, whereas working memory was almost unimpaired. These alterations are comparable with those found in the partial trisomy chromosome 16 murine models of DS and suggest a causative role of DYRK1A in mental retardation and in motor anomalies of DS.

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    • "Overexpression of DYRK1A has also been implicated in the motor alterations [9], [14] found in the DS population [15]–[17]. Although most studies have failed to detect anomalies in motor function or coordination in the most commonly used segmental trisomic model of DS, i.e., the TS mouse [18]–[20], in various experimental settings, these animals exhibit hyperactivity that is indicative of altered attention [20]–[22], which can compromise their cognitive performance during multiple tasks. "
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    ABSTRACT: Down syndrome (DS) phenotypes result from the overexpression of several dosage-sensitive genes. The DYRK1A (dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1A) gene, which has been implicated in the behavioral and neuronal alterations that are characteristic of DS, plays a role in neuronal progenitor proliferation, neuronal differentiation and long-term potentiation (LTP) mechanisms that contribute to the cognitive deficits found in DS. The purpose of this study was to evaluate the effect of Dyrk1A overexpression on the behavioral and cognitive alterations in the Ts65Dn (TS) mouse model, which is the most commonly utilized mouse model of DS, as well as on several neuromorphological and electrophysiological properties proposed to underlie these deficits. In this study, we analyzed the phenotypic differences in the progeny obtained from crosses of TS females and heterozygous Dyrk1A (+/-) male mice. Our results revealed that normalization of the Dyrk1A copy number in TS mice improved working and reference memory based on the Morris water maze and contextual conditioning based on the fear conditioning test and rescued hippocampal LTP. Concomitant with these functional improvements, normalization of the Dyrk1A expression level in TS mice restored the proliferation and differentiation of hippocampal cells in the adult dentate gyrus (DG) and the density of GABAergic and glutamatergic synapse markers in the molecular layer of the hippocampus. However, normalization of the Dyrk1A gene dosage did not affect other structural (e.g., the density of mature hippocampal granule cells, the DG volume and the subgranular zone area) or behavioral (i.e., hyperactivity/attention) alterations found in the TS mouse. These results suggest that Dyrk1A overexpression is involved in some of the cognitive, electrophysiological and neuromorphological alterations, but not in the structural alterations found in DS, and suggest that pharmacological strategies targeting this gene may improve the treatment of DS-associated learning disabilities.
    PLoS ONE 09/2014; 9(9):e106572. DOI:10.1371/journal.pone.0106572 · 3.23 Impact Factor
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    • "It was previously shown that DYRK1A overexpression induces functional alterations in prefrontal cortex of mBACtgDyrk1a mice with dendritic alterations and anomalous NMDAR-mediated longterm potentiation (Thomazeau et al., 2014). The first model overexpressing Dyrk1a was constructed using a rat cDNA under the control of a metallothionein promoter (Altafaj et al., 2001); that model also exhibits motor alterations in open field activity but the phenotypes observed using the Morris paradigm were less significant in TgDyrk1a than those highlighted in our murine BAC model. A second model, constructed using a human BAC (Ahn et al., 2006), does not show any deficit in rotarod testing, but exhibits impairment in the Morris paradigm, with almost no learning after 8 sessions. "
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    ABSTRACT: Cognitive deficits in Down syndrome (DS) have been linked to increased synaptic inhibition, leading to an imbalance of excitation/inhibition (E/I). Various mouse models and studies from human brains have implicated an HSA21 gene, the serine/threonine kinase DYRK1A, as a candidate for inducing cognitive dysfunction. Here, consequences of alterations in Dyrk1a dosage were assessed in mouse models with varying copy numbers of Dyrk1a: mBACtgDyrk1a, Ts65Dn and Dp(16)1Yey (with 3 gene copies) and Dyrk1a(+/−) (one functional copy). Molecular (i.e. immunoblotting/immunohistochemistry) and behavioral analyses (e.g., rotarod, Morris water maze, Y-maze) were performed in mBACtgDyrk1a mice. Increased expression of DYRK1A in mBACtgDyrk1a induced molecular alterations in synaptic plasticity pathways, particularly expression changes in GABAergic and glutaminergic related proteins. Similar alterations were observed in models with partial trisomy of MMU16, Ts65Dn and Dp(16)1Yey, and were reversed in the Dyrk1a(+/−) model. Dyrk1a overexpression produced an increased number and signal intensity of GAD67 positive neurons, indicating enhanced inhibition pathways in three different models: mBACtgDyrk1a, hYACtgDyrk1a and Dp(16)1Yey. Functionally, Dyrk1a overexpression protected mice from PTZ-induced seizures related to GABAergic neuron plasticity. Our study shows that DYRK1A overexpression affects pathways involved in synaptogenesis and synaptic plasticity and influences E/I balance towards inhibition. Inhibition of DYRK1A activity offers a therapeutic target for DS, but its inhibition/activation may also be relevant for other psychiatric diseases with E/I balance alterations.
    Neurobiology of Disease 09/2014; 69. DOI:10.1016/j.nbd.2014.04.016 · 5.08 Impact Factor
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    • "However, until recently, the functional role of DYRK1A in cancer is largely obscure. Interestingly, DYRK1A is localized within the Down Syndrome critical region (DSCR) on chromosome 21, and is considered to be a strong candidate gene for this genetic disorder [12], [13]. Adult with Down syndrome (DS) have a markedly decreased risk of developing cancers compared with that without DS [14], [15]. "
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    ABSTRACT: Acute myeloid leukemia (AML), caused by abnormal proliferation and accumulation of hematopoietic progenitor cells, is one of the most common malignancies in adults. We reported here DYRK1A expression level was reduced in the bone marrow of adult AML patients, comparing to normal controls. Overexpression of DYRK1A inhibited the proliferation of AML cell lines by increasing the proportion of cells undergoing G0/G1 phase. We reasoned that the proliferative inhibition was due to downregulation of c-Myc by DYRK1A, through mediating its degradation. Moreover, overexpression of c-Myc markedly reversed AML cell growth inhibition induced by DYRK1A. DYRK1A also had significantly lower expression in relapsed/refractory AML patients, comparing to newly-diagnosed AML patients, which indicated the role of DYRK1A in chemoresistance of AML. Our study provided functional evidences for DYRK1A as a potential tumor suppressor in AML.
    PLoS ONE 06/2014; 9(6):e98853. DOI:10.1371/journal.pone.0098853 · 3.23 Impact Factor
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