Evidence that increased Kcnj6 gene dose is necessary for deficits in behavior and dentate gyrus synaptic plasticity in the Ts65Dn mouse model of Down syndrome.
- Authors
- Kleschevnikov, Alexander M; Yu, Jessica; Kim, Jeesun; Lysenko, Larisa V; Zeng, Zheng; Yu, Y Eugene; Mobley, William C
- Year
- 2017
- Journal
- Neurobiology of disease
- PMID
- 28342823
- DOI
- 10.1016/j.nbd.2017.03.009
- PMCID
- PMC5446050
Down syndrome (DS), trisomy 21, is caused by increased dose of genes present on human chromosome 21 (HSA21). The gene-dose hypothesis argues that a change in the dose of individual genes or regulatory sequences on HSA21 is necessary for creating DS-related phenotypes, including cognitive impairment. We focused on a possible role for Kcnj6, the gene encoding Kir3.2 (Girk2) subunits of a G-protein-coupled inwardly-rectifying potassium channel. This gene resides on a segment of mouse Chromosome 16 that is present in one extra copy in the genome of the Ts65Dn mouse, a well-studied genetic model of DS. Kir3.2 subunit-containing potassium channels serve as effectors for a number of postsynaptic metabotropic receptors including GABAB receptors. Several studies raise the possibility that increased Kcnj6 dose contributes to synaptic and cognitive abnormalities in DS. To assess directly a role for Kcnj6 gene dose in cognitive deficits in DS, we produced Ts65Dn mice that harbor only 2 copies of Kcnj6 (Ts65Dn:Kcnj6++- mice). The reduction in Kcnj6 gene dose restored to normal the hippocampal level of Kir3.2. Long-term memory, examined in the novel object recognition test with the retention period of 24h, was improved to the level observed in the normosomic littermate control mice (2N:Kcnj6++). Significantly, both short-term and long-term potentiation (STP and LTP) was improved to control levels in the dentate gyrus (DG) of the Ts65Dn:Kcnj6++- mouse. In view of the ability of fluoxetine to suppress Kir3.2 channels, we asked if fluoxetine-treated DG slices of Ts65Dn:Kcnj6+++ mice would rescue synaptic plasticity. Fluoxetine increased STP and LTP to control levels. These results are evidence that increased Kcnj6 gene dose is necessary for synaptic and cognitive dysfunction in the Ts65Dn mouse model of DS. Strategies aimed at pharmacologically reducing channel function should be explored for enhancing cognition in DS.
Changes in body weight. The body weight was reduced in both Ts65Dn:Kcnj6+++ and Ts65Dn:Kcnj6++β vs. 2N:Kcnj6++ mice at all ages. There was no difference between the body weight of Ts65Dn:Kcnj6+++ vs. Ts65Dn:Kcnj6++β in young animals (1β4 months). However, the body weight was increased in older (5β6 mo and 9β12 mo) Ts65Dn:Kcnj6++β vs. Ts65Dn:Kcnj6+++ mice. The animal numbers and other statistical parameters are given in Table 1.
Hippocampal levels of proteins. A. Level of Kir3.1 was not altered, while level of Kir3.2 was increased in Ts65Dn:Kcnj6+++ (n = 6) vs. 2N:Kcnj6++ (n = 5) samples. B. There was no difference in the levels of either Kir3.1 or Kir3.2 in Ts65Dn:Kcnj6++β (n = 5) vs. 2N:Kcnj6++ (n = 6) samples. C. Kir3.1 level was not different, but Kir3.2 was increased in Ts65Dn:Kcnj6+++ (n = 5) vs. Ts65Dn:Kcnj6++β (n = 6) mice.
Spontaneous locomotion. A. Ambulatory distance was significantly increased in both Ts65Dn:Kcnj6+++ (n = 12) and Ts65Dn:Kcnj6++β (n = 14) vs. 2N:Kcnj6++ (n = 19) mice. No difference between Ts65Dn:Kcnj6+++ vs. Ts65Dn:Kcnj6++β mice was observed. B. Ambulatory time was also increased in both Ts65Dn:Kcnj6+++ and Ts65Dn:Kcnj6++β mice. C, D. Ambulatory distance and ambulatory time spent on periphery were greater in Ts65Dn:Kcnj6+++ vs. 2N:Kcnj6++ mice, but not different in Ts65Dn:Kcnj6++β vs. 2N:Kcnj6++ animals.
Working memory and exploratory activity in the Y-maze. A. The rate of spontaneous alternations was reduced in both Ts65Dn:Kcnj6+++ (n = 12) and Ts65Dn:Kcnj6++β (n = 14) vs. 2N:Kcnj6++ (n = 19) mice. Reduction of Kcnj6 gene dose had no effect on performance of Ts65Dn mice (p = 0.84 for Ts65Dn:Kcnj6+++ vs. Ts65Dn:Kcnj6++β). B. Number of βarm entriesβ during the Y-maze test was greater in Ts65Dn:Kcnj6+++ vs. 2N:Kcnj6++ mice. The number of arm entries was reduced in Ts65Dn:Kcnj6++β mice to the level of 2N:Kcnj6++ controls.
Long-term memory. Performance in the novel object recognition test with a retention period of 24 h. A: Time for object exploration was not different between genotypes. B: The discrimination index was reduced in Ts65Dn:Kcnj6+++ (n = 12) vs. 2N:Kcnj6++ (n = 19) mice, but it was increased in Ts65Dn:Kcnj6++β (n = 14) mice to the level observed in 2N:Kcnj6++ control mice.
Synaptic plasticity: effect of the Kcnj6 gene dose on STP and LTP in DG. A. Averaged changes in the initial slope of field EPSP during the experiment. B. Averaged values for STP (1β15 min) and LTP (30β60 min). STP and LTP were reduced in Ts65Dn:Kcnj6+++ (n = 8) vs. 2N:Kcnj6++ (n = 12) slices. Both parameters were normalized in slices from Ts65Dn:Kcnj6++β (n = 11) mice.
Synaptic plasticity: Effect of fluoxetine on STP and LTP in DG. A. Averaged changes in the initial slope of field EPSP during the experiment. Application of fluoxetine or vehicle marked by the black line under the graph. B. Averaged values for STP (1β15 min) and LTP (30β60 min). Both STP and LTP were reduced in Ts65Dn (n = 14) vs. 2N (n = 13) slices. Fluoxetine increased both parameters in Ts65Dn slices (n = 10) to control levels, but did not affect these parameters in 2N slices (n = 7).
| Name | Type |
|---|---|
| 2N local | cohort |
| 2N controls local | cohort |
| 2N:Kcnj6++ local | cohort |
| 2N mice local | cohort |
| 3-4 month old mice local | cohort |
| 5HT-1A local | drug |
| A1 local | drug |
| AAV | drug |
| abnormal synaptic plasticity local | phenotype |
| alternation rate local | phenotype |
| Alzheimerβs disease | phenotype |
| Ambulatory distance local | phenotype |
| Ambulatory time local | phenotype |
| anxiety | phenotype |
| APP | gene |
| aprotinin | drug |
| arm entries local | phenotype |
| artificial cerebrospinal fluid | drug |
| BCA protein assay kit | drug |
| behavioral deficits | phenotype |
| Behavioral testing | phenotype |
| blindness | phenotype |
| body weight | phenotype |
| CaCl2 | drug |
| cerebellum | anatomy |
| Clarity Western ECL Substrate local | drug |
| cognition | phenotype |
| compromised retrograde axonal transport of NGF local | phenotype |
| deficient cognition local | phenotype |
| deficient hippocampus-dependent long-term memory local | phenotype |
| degeneration of cholinergic neurons local | phenotype |
| dentate gyrus | anatomy |
| Dentate gyrus (DG) local | anatomy |
| diminished LTP local | phenotype |
| Discrimination index local | phenotype |
| Down syndrome | phenotype |
| Dp(16)1/+ model local | cohort |
| Dyrk1A | gene |
| EDTA | drug |
| enlargement of early endosomes local | phenotype |
| ethanol consumption | phenotype |
| exploratory activity local | phenotype |
| exploratory behavior | phenotype |
| fluoxetine | drug |
| Fluoxetine hydrochloride local | drug |
| GABA | phenotype |
| GABAB receptor | drug |
| GABAB receptor antagonist | drug |
| glucose | drug |
| glutamate | drug |
| goat anti-mouse secondary antibody local | drug |
| goat anti-rabbit IgG-HRP conjugate local | drug |
| hippocampal CA1 region | anatomy |
| hippocampus | anatomy |
| Humans with Down syndrome local | cohort |
| ImageJ | drug |
| increased GABAergic inhibition local | phenotype |
| Increased inhibition local | phenotype |
| intellectual disability | phenotype |
| isoflurane | drug |
| KCl | drug |
| KCNJ3 | gene |
| Kcnj6 | gene |
| Kcnj6++ local | variant |
| Kcnj6+/β local | variant |
| Kcnj6+/+ mice local | cohort |
| Kcnj6+/β mice local | cohort |
| KCNJ6 missense mutation (pore-forming domain) local | variant |
| Keppen-Lubinsky syndrome local | phenotype |
| Kir3.1 local | drug |
| Kir3.2 local | drug |
| Kir3.2 G to S missense mutation local | variant |
| Kir3.2 potassium channel local | drug |
| Kir3.2 three-nucleotide deletion local | variant |
| Laemmli Sample Buffer local | drug |
| leupeptin | drug |
| locomotion | phenotype |
| locomotor activity | phenotype |
| long-term memory | phenotype |
| long-term potentiation | phenotype |
| long-term potentiation (LTP) | phenotype |
| LTP | phenotype |
| M2 receptor | drug |
| MgSO4 | drug |
| mice | cohort |
| microcephaly | phenotype |
| Middle Molecular Layer local | anatomy |
| Mouse genetic models local | cohort |
| Mouse genetic models of DS local | cohort |
| mouse monoclonal anti-Ξ²-actin primary antibody local | drug |
| Mx1 | gene |
| Na3VO4 | drug |
| Na-deoxycholate local | drug |
| NaF local | drug |
| NaH2PO4 | drug |
| NaHCO3 | drug |
| neocortex | anatomy |
| neurogenesis | phenotype |
| Neurophysiology local | phenotype |
| NGF | drug |
| novel object recognition memory local | phenotype |
| NP-40 | drug |
| object recognition | phenotype |
| Pde6brd1 local | gene |
| Pde6brd1_homozygosity local | variant |
| pepstatin | drug |
| PMSF | drug |
| protease inhibitor cocktail | drug |
| Resting time local | phenotype |
| retinal degeneration local | phenotype |
| RIPA buffer | drug |
| serotonin | drug |
| severe developmental delay local | phenotype |
| short hairpin RNA against Dyrk1A local | drug |
| short-term potentiation | phenotype |
| Short-term potentiation (STP) local | phenotype |
| Sod1 | gene |
| SOD1 transgenic mice local | cohort |
| spontaneous locomotor activity local | phenotype |
| stereotypy | phenotype |
| synaptic plasticity | phenotype |
| SYNJ1 | gene |
| TBS-T local | drug |
| thalamus | anatomy |
| Thigmotaxis local | phenotype |
| Tris-Glycine gel local | drug |
| Tris-Glycine running buffer local | drug |
| Ts65Dn local | cohort |
| Ts65Dn:Kcnj6+++ local | cohort |
| Ts65Dn:Kcnj6++- local | cohort |
| Ts65Dn:Kcnj6++β local | cohort |
| Ts65Dn mice local | cohort |
| Ts65Dn mouse model local | cohort |
| Ts65Ds mouse local | cohort |
| Velocity local | phenotype |
| weaver phenotype local | phenotype |
| Weaver phenotype local | phenotype |
| working memory | phenotype |
| Ξ²-actin | gene |
No uploaded files.
In this knowledge base
| Title | Year | PMID |
|---|---|---|
| Alcohol reverses the effects of KCNJ6 (GIRK2) noncoding variants on excitability of human glutamatergic neurons. | 2023 | 36207584 |
External
| Title | Authors | Journal | Year | Link |
|---|---|---|---|---|
| Identification of Neurite Outgrowth and Synaptic Plasticity-related Genes Showing Sustained Hypermethylation of Promoter Region in the Hippocampal Dentate Gyrus of Rats Exposed Maternally To Neurotoxicants To Induce Persistent Disruption of Hippocampal Neurogenesis. | Ojiro R et al. | β | 2025 | β |
| Amyloid-Ξ² oligomers trigger sex-dependent inhibition of GIRK channel activity in hippocampal neurons in mice. | Luo H et al. | β | 2024 | β |
| Domain-selective and sex-dependent regulation of learning and memory in mice by GIRK channel activity in CA1 pyramidal neurons of the dorsal hippocampus. | Luo H et al. | β | 2024 | β |
| Identifying the joint signature of brain atrophy and gene variant scores in Alzheimer's Disease. | Cruciani F et al. | β | 2024 | β |
| Lamivudine modulates the expression of neurological impairment-related genes and LINE-1 retrotransposons in brain tissues of a Down syndrome mouse model. | Borgognone A et al. | β | 2024 | β |
| Pleiotropic effects of trisomy and pharmacologic modulation on structural, functional, molecular, and genetic systems in a Down syndrome mouse model. | Llambrich S et al. | β | 2024 | β |
| Transcranial Direct Current Stimulation in neurogenetic syndromes: new treatment perspectives for Down syndrome? | Faralli A et al. | β | 2024 | β |
| Alcohol reverses the effects of KCNJ6 (GIRK2) noncoding variants on excitability of human glutamatergic neurons. | Popova D et al. | β | 2023 | β |
| Brain circuit pathology in Down syndrome: from neurons to neural networks. | Bartesaghi R | β | 2023 | β |
| Pleiotropic effects of trisomy and pharmacologic modulation on structural, functional, molecular, and genetic systems in a Down syndrome mouse model | Llambrich S et al. | β | 2023 | β |
| Potassium Channels in Parkinson's Disease: Potential Roles in Its Pathogenesis and Innovative Molecular Targets for Treatment. | Chen X et al. | β | 2023 | β |
| A Method for Bridging Population-Specific Genotypes to Detect Gene Modules Associated with Alzheimer's Disease. | Dai Y et al. | β | 2022 | β |
| Enhanced GIRK2 channel signaling in Down syndrome: A feasible role in the development of abnormal nascent neural circuits. | Kleschevnikov AM | β | 2022 | β |
| GABA<sub>B</sub> Receptors and Cognitive Processing in Health and Disease. | Vlachou S | β | 2022 | β |
| GIRK2 Channels in Down Syndrome and Alzheimer's Disease. | Kleschevnikov A | β | 2022 | β |
| Impact of increased APP gene dose in Down syndrome and the Dp16 mouse model. | Sawa M et al. | β | 2022 | β |
| Neuronal G protein-gated K<sup>+</sup> channels. | Luo H et al. | β | 2022 | β |
| Prenatal and Postnatal Pharmacotherapy in Down Syndrome: The Search to Prevent or Ameliorate Neurodevelopmental and Neurodegenerative Disorders. | Bartesaghi R et al. | β | 2022 | β |
| Cholinergic neurodegeneration in Alzheimer disease mouse models. | Shekari A et al. | β | 2021 | β |
| Nuclear Reorganization in Hippocampal Granule Cell Neurons from a Mouse Model of Down Syndrome: Changes in Chromatin Configuration, Nucleoli and Cajal Bodies. | Puente-Bedia A et al. | β | 2021 | β |
| Restoring neuronal chloride homeostasis with anti-NKCC1 gene therapy rescues cognitive deficits in a mouse model of Down syndrome. | Parrini M et al. | β | 2021 | β |
| Targeting increased levels of APP in Down syndrome: Posiphen-mediated reductions in APP and its products reverse endosomal phenotypes in the Ts65Dn mouse model. | Chen XQ et al. | β | 2021 | β |
| Therapeutic potential of targeting G protein-gated inwardly rectifying potassium (GIRK) channels in the central nervous system. | Jeremic D et al. | β | 2021 | β |
| A missense point mutation in nerve growth factor (NGF<sup>R100W</sup>) results in selective peripheral sensory neuropathy. | Yang W et al. | β | 2020 | β |
| Genetic and epigenetic pathways in Down syndrome: Insights to the brain and immune system from humans and mouse models. | Yu YE et al. | β | 2020 | β |
| Intellectual Disability and Potassium Channelopathies: A Systematic Review. | Kessi M et al. | β | 2020 | β |
| Modeling Down syndrome in animals from the early stage to the 4.0 models and next. | MuΓ±iz Moreno MDM et al. | β | 2020 | β |
| Repeated Methylglyoxal Treatment Depletes Dopamine in the Prefrontal Cortex, and Causes Memory Impairment and Depressive-Like Behavior in Mice. | Szczepanik JC et al. | β | 2020 | β |
| Down syndrome. | Rafii MS et al. | β | 2019 | β |
| Spaced training improves learning in Ts65Dn and Ube3a mouse models of intellectual disabilities. | Lauterborn JC et al. | β | 2019 | β |
| Unbalanced dendritic inhibition of CA1 neurons drives spatial-memory deficits in the Ts2Cje Down syndrome model. | Valbuena S et al. | β | 2019 | β |
| Developmental excitatory-to-inhibitory GABA polarity switch is delayed in Ts65Dn mice, a genetic model of Down syndrome. | Lysenko LV et al. | β | 2018 | β |
| GABAergic over-inhibition, a promising hypothesis for cognitive deficits in Down syndrome. | Zorrilla de San Martin J et al. | β | 2018 | β |
| Targeting trisomic treatments: optimizing Dyrk1a inhibition to improve Down syndrome deficits. | Stringer M et al. | β | 2017 | β |