| 1. |
- Gouras, Gunnar, et al.
(författare)
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The Inside-Out Amyloid Hypothesis and Synapse Pathology in Alzheimer's Disease.
- 2014
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Ingår i: Neurodegenerative Diseases. - : S. Karger AG. - 1660-2862 .- 1660-2854. ; 13:2-3, s. 142-146
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Tidskriftsartikel (refereegranskat)abstract
- Cumulative evidence in brains and cultured neurons of Alzheimer's disease (AD) transgenic mouse models, as well as in human postmortem AD brains, highlights that age-related increases in β-amyloid peptide (Aβ), particularly in endosomes near synapses, are involved in early synapse dysfunction. Our immunoelectron microscopy and high-resolution immunofluorescence microscopy studies show that this early subcellular Aβ accumulation leads to progressive Aβ aggregation and pathology, particularly within dystrophic neurites and synapses. These studies confirm that neuritic/synaptic Aβ accumulation is the nidus of plaque formation. Aβ-dependent synapse pathology in AD models is modulated by synaptic activity and is plaque independent. The amyloid precursor protein (APP) is normally transported down neurites and appears to be preferentially processed to Aβ at synapses. Synapses are sites of early Aβ accumulation and aberrant tau phosphorylation in AD, which alter the synaptic composition at early stages of the disease. Elucidating the normal role of APP, and potentially of Aβ, at synapses should provide important insights into the mechanism(s) of Aβ-induced synapse dysfunction in AD and how to therapeutically mitigate these dysfunctions. © 2013 S. Karger AG, Basel.
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| 2. |
- Huyghe, Deborah, et al.
(författare)
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Glutamine Synthetase Stability and Subcellular Distribution in Astrocytes are Regulated by G-Aminobutyric Type B Receptors.
- 2014
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 289:42, s. 28808-28815
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Tidskriftsartikel (refereegranskat)abstract
- Emerging evidence suggests that functional γ-aminobutyric acid B receptors (GABABRs) are expressed by astrocytes within the mammalian brain. GABABRs are heterodimeric G-protein coupled receptors that are composed of R1/R2 subunits. To date, they have been characterized in neurons as the principal mediators of sustained inhibitory signaling, however their roles in astrocytic physiology have been ill defined. Here we reveal that the cytoplasmic tail of the GABABR2 subunit binds directly to the astrocytic protein glutamine synthetase (GS) and that this interaction determines the subcellular localization of GS. We further demonstrate that the binding of GS to GABABR2 increases the steady state expression levels of GS in heterologous cells and in mouse primary astrocyte culture. Mechanistically this increased stability of GS in the presence of GABABR2 occurs via reduced proteasomal degradation. Collectively, our results suggest a novel role for GABABRs as regulators of GS stability. Given the critical role that GS plays in the glutamine-glutamate cycle, astrocytic GABABRs may play a critical role in supporting both inhibitory and excitatory neurotransmission.
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| 3. |
- Klementieva, Oxana, et al.
(författare)
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Detection of pre-plaque amyloid aggregation using FTIR
- 2014
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5279 .- 1552-5260. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Alzheimer's disease (AD) is characterized by misfolding and aggregation of naturally occurring beta-amyloid peptides (Aβ). These aggregates are thought to be pathogenic to neurons, although the conformation of the pathogenic Aβ species remains unclear. Biochemical extraction methods and different microscopy techniques (TEM, confocal) can be used to identify pathogenic Aβ species in the brain, although such methods can alter protein conformation or are n ot designed to determine structural details of protein assemblies.
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| 4. |
- Martinsson, Isak, et al.
(författare)
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APP depletion alters selective pre- and post-synaptic proteins
- 2019
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Ingår i: Molecular and Cellular Neuroscience. - : Elsevier BV. - 1044-7431 .- 1095-9327. ; 95, s. 86-95
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Tidskriftsartikel (refereegranskat)abstract
- The normal role of Alzheimer's disease (AD)-linked amyloid precursor protein (APP) in the brain remains incompletely understood. Previous studies have reported that lack of APP has detrimental effects on spines and electrophysiological parameters. APP has been described to be important in synaptic pruning during development. The effect of APP knockout on mature synapses is complicated by this role in development. We previously reported on differential changes in synaptic proteins and receptors in APP mutant AD transgenic compared to wild-type neurons, which revealed selective decreases in levels of pre- and post-synaptic proteins, including of surface glutamate receptors. In the present study, we undertook a similar analysis of synaptic composition but now in APP knockout compared to wild-type mouse neurons. Here we demonstrate alterations in levels of selective pre- and post-synaptic proteins and receptors in APP knockout compared to wild-type mouse primary neurons in culture and brains of mice in youth and adulthood. Remarkably, we demonstrate selective increases in levels of synaptic proteins, such as GluA1, in neurons with APP knockout and with RNAi knockdown, which tended to be opposite to the reductions seen in AD transgenic APP mutant compared to wild-type neurons. These data reinforce that APP is important for the normal composition of synapses.
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