| 1. |
- Agholme, Lotta, et al.
(författare)
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Low-dose γ-secretase inhibition increases secretion of Aβ peptides and intracellular oligomeric Aβ.
- 2017
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Ingår i: Molecular and cellular neurosciences. - : Elsevier BV. - 1095-9327 .- 1044-7431. ; 85, s. 211-219
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Tidskriftsartikel (refereegranskat)abstract
- γ-Secretase inhibitors have been considered promising drug candidates against Alzheimer's disease (AD) due to their ability to reduce amyloid-β (Aβ) production. However, clinical trials have been halted due to lack of clinical efficacy and/or side effects. Recent in vitro studies suggest that low doses of γ-secretase inhibitors may instead increase Aβ production. Using a stem cell-derived human model of cortical neurons and low doses of the γ-secretase inhibitor DAPT, the effects on a variety of Aβ peptides were studied using mass spectrometry. One major focus was to develop a novel method for specific detection of oligomeric Aβ (oAβ), and this was used to study the effects of low-dose γ-secretase inhibitor treatment on intracellular oAβ accumulation. Low-dose treatment (2 and 20nM) with DAPT increased the secretion of several Aβ peptides, especially Aβx-42. Furthermore, using the novel method for oAβ detection, we found that 2nM DAPT treatment of cortical neurons resulted in increased oAβ accumulation. Thus, low dose-treatment with DAPT causes both increased production of long, aggregation-prone Aβ peptides and accumulation of intracellular Aβ oligomers, both believed to contribute to AD pathology.
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| 2. |
- Ansell - Schultz, Anna, et al.
(författare)
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Reduced retromer function results in the accumulation of amyloid-beta oligomers
- 2018
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Ingår i: Molecular and Cellular Neuroscience. - : Academic Press. - 1044-7431 .- 1095-9327. ; 93, s. 18-26
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimers disease (AD) is a neurodegenerative disorder characterized by a progressive loss of multiple cognitive functions. Accumulation of amyloid beta oligomers (oA beta) play a major role in the neurotoxicity associated with the disease process. One of the early affected brain regions is the hippocampus, wherein a reduction of the vacuolar protein sorting-associated protein 35 (VPS35), the core protein comprising the retromer complex involved in cellular cargo sorting, has been identified. To investigate the role of the retromer function on the accumulation and clearance of oA beta, we reduced retromer function by selectively inhibiting VPS35 gene expression using siRNA in differentiated neuronal SH-SY5Y cells. As cell-to-cell transfer of oA beta to new brain regions is believed to be important for disease progression we investigated the effect of VPS35 reduction both in cells with direct uptake of oA beta and in cells receiving oA beta from donor cells. We demonstrate that reduced retromer function increases oA beta accumulation in both cell systems, both the number of cells containing intracellular oA beta and the amount within them. This effect was shown at different time points and regardless if the AD originated from the extracellular milieu or via a direct neuronal cell-to-cell transfer. Interestingly, not only did reduced VPS35 cause oA beta accumulation, but oA beta treatment alone also lead to a reduction of VPS35 protein content. The accumulated oA beta seems to co-localize with VPS35 and early endosome markers. Together, these findings provide evidence that reduced retromer function decreases the ability for neurons to transport and clear neurotoxic oA beta received through different routes resulting in the accumulation of oA beta. Thus, enhancing retromer function may be a potential therapeutic strategy to slow down the pathophysiology associated with the progression of AD.
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| 3. |
- Cohen, Ann D, et al.
(författare)
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Fluid and PET biomarkers for amyloid pathology in Alzheimer's disease.
- 2019
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Ingår i: Molecular and cellular neurosciences. - : Elsevier BV. - 1095-9327 .- 1044-7431. ; 97, s. 3-17
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Forskningsöversikt (refereegranskat)abstract
- Alzheimer's disease (AD) is characterized by amyloid plaques and tau pathology (neurofibrillary tangles and neuropil threads). Amyloid plaques are primarily composed of aggregated and oligomeric β-amyloid (Aβ) peptides ending at position 42 (Aβ42). The development of fluid and PET biomarkers for Alzheimer's disease (AD), has allowed for detection of Aβ pathology in vivo and marks a major advancement in understanding the role of Aβ in Alzheimer's disease (AD). In the recent National Institute on Aging and Alzheimer's Association (NIA-AA) Research Framework, AD is defined by the underlying pathology as measured in patients during life by biomarkers (Jack et al., 2018), while clinical symptoms are used for staging of the disease. Therefore, sensitive, specific and robust biomarkers to identify brain amyloidosis are central in AD research. Here, we discuss fluid and PET biomarkers for Aβ and their application.
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| 4. |
- Heurling, Kerstin, et al.
(författare)
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Synaptic vesicle protein 2A as a potential biomarker in synaptopathies
- 2019
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Ingår i: Molecular and Cellular Neuroscience. - : Elsevier. - 1044-7431 .- 1095-9327. ; 97, s. 34-42
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Tidskriftsartikel (refereegranskat)abstract
- Measuring synaptic density in vivo using positron emission tomography (PET) imaging-based biomarkers targeting the synaptic vesicle protein 2A (SV2A) has received much attention recently due to its potential research and clinical applications in synaptopathies, including neurodegenerative and psychiatric diseases. Fluid-based biomarkers in proteinopathies have previously been suggested to provide information on pathology and disease status that is complementary to PET-based measures, and the same can be hypothesized with respect to SV2A. This review provides an overview of the current state of SV2A PET imaging as a biomarker of synaptic density, the potential role of fluid-based biomarkers for SV2A, and related future perspectives.
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| 5. |
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| 6. |
- Lindström, Veronica, et al.
(författare)
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Extensive uptake of α-synuclein oligomers in astrocytes results in sustained intracellular deposits and mitochondrial damage
- 2017
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Ingår i: Molecular and Cellular Neuroscience. - : Elsevier BV. - 1044-7431 .- 1095-9327. ; 82, s. 143-156
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Tidskriftsartikel (refereegranskat)abstract
- The presence of Lewy bodies, mainly consisting of aggregated α-synuclein, is a pathological hallmark of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). The α-synuclein inclusions are predominantly found in neurons, but also appear frequently in astrocytes. However, the pathological significance of α-synuclein inclusions in astrocytes and the capacity of glial cells to clear toxic α-synuclein species remain unknown. In the present study we investigated uptake, degradation and toxic effects of oligomeric α-synuclein in a co-culture system of primary neurons, astrocytes and oligodendrocytes. Alpha-synuclein oligomers were found to co-localize with the glial cells and the astrocytes were found to internalize particularly large amounts of the protein. Following ingestion, the astrocytes started to degrade the oligomers via the lysosomal pathway but, due to incomplete digestion, large intracellular deposits remained. Moreover, the astrocytes displayed mitochondrial abnormalities. Taken together, our data indicate that astrocytes play an important role in the clearance of toxic α-synuclein species from the extracellular space. However, when their degrading capacity is overburdened, α-synuclein deposits can persist and result in detrimental cellular processes.
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| 7. |
- Ling, Helen, et al.
(författare)
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Neurological consequences of traumatic brain injuries in sports.
- 2015
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Ingår i: Molecular and cellular neurosciences. - : Elsevier BV. - 1095-9327 .- 1044-7431. ; 66:Part B, s. 114-122
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Tidskriftsartikel (refereegranskat)abstract
- Traumatic brain injury (TBI) is common in boxing and other contact sports. The long term irreversible and progressive aftermath of TBI in boxers depicted as punch drunk syndrome was described almost a century ago and is now widely referred as chronic traumatic encephalopathy (CTE). The short term sequelae of acute brain injury including subdural haematoma and catastrophic brain injury may lead to death, whereas mild TBI, or concussion, causes functional disturbance and axonal injury rather than gross structural brain damage. Following concussion, symptoms such as dizziness, nausea, reduced attention, amnesia and headache tend to develop acutely but usually resolve within a week or two. Severe concussion can also lead to loss of consciousness. Despite the transient nature of the clinical symptoms, functional neuroimaging, electrophysiological, neuropsychological and neurochemical assessments indicate that the disturbance of concussion takes over a month to return to baseline and neuropathological evaluation shows that concussion-induced axonopathy may persist for years. The developing brains in children and adolescents are more susceptible to concussion than adult brain. The mechanism by which acute TBI may lead to the neurodegenerative process of CTE associated with tau hyperphosphorylation and the development of neurofibrillary tangles (NFTs) remains speculative. Focal tau-positive NFTs and neurites in close proximity to focal axonal injury and foci of microhaemorrhage and the predilection of CTE-tau pathology for perivascular and subcortical regions suggest that acute TBI-related axonal injury, loss of microvascular integrity, breach of the blood brain barrier, resulting inflammatory cascade and microglia and astrocyte activation are likely to be the basis of the mechanistic link of TBI and CTE. This article provides an overview of the acute and long-term neurological consequences of TBI in sports. Clinical, neuropathological and the possible pathophysiological mechanisms are discussed. This article is part of a Special Issue entitled 'Traumatic Brain Injury'.
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| 8. |
- 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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| 9. |
- Schöll, Michael, 1980, et al.
(författare)
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Biomarkers for tau pathology.
- 2019
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Ingår i: Molecular and cellular neurosciences. - : Elsevier BV. - 1095-9327 .- 1044-7431. ; 97, s. 18-33
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Forskningsöversikt (refereegranskat)abstract
- The aggregation of fibrils of hyperphosphorylated and C-terminally truncated microtubule-associated tau protein characterizes 80% of all dementia disorders, the most common neurodegenerative disorders. These so-called tauopathies are hitherto not curable and their diagnosis, especially at early disease stages, has traditionally proven difficult. A keystone in the diagnosis of tauopathies was the development of methods to assess levels of tau protein in vivo in cerebrospinal fluid, which has significantly improved our knowledge about these conditions. Tau proteins have also been measured in blood, but the importance of tau-related changes in blood is still unclear. The recent addition of positron emission tomography ligands to visualize, map and quantify tau pathology has further contributed with information about the temporal and spatial characteristics of tau accumulation in the living brain. Together, the measurement of tau with fluid biomarkers and positron emission tomography constitutes the basis for a highly active field of research. This review describes the current state of biomarkers for tau biomarkers derived from neuroimaging and from the analysis of bodily fluids and their roles in the detection, diagnosis and prognosis of tau-associated neurodegenerative disorders, as well as their associations with neuropathological findings, and aims to provide a perspective on how these biomarkers might be employed prospectively in research and clinical settings.
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| 10. |
- Virel, Ana, et al.
(författare)
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H-1 NMR profiling of the 6-OHDA parkinsonian rat brain reveals metabolic alterations and signs of recovery after N-acetylcysteine treatment
- 2019
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Ingår i: Molecular and Cellular Neuroscience. - : Elsevier BV. - 1044-7431 .- 1095-9327. ; 98, s. 131-139
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Tidskriftsartikel (refereegranskat)abstract
- Parkinson's disease is the second most common neurodegenerative disease caused by degeneration of dopamine neurons in the substantia nigra. The origin and causes of dopamine neurodegeneration in Parkinson's disease are not well understood but oxidative stress may play an important role in its onset. Much effort has been dedicated to find biomarkers indicative of oxidative stress and neurodegenerative processes in parkinsonian brains. By using proton nuclear magnetic resonance (H-1 NMR) to identify and quantify key metabolites, it is now possible to elucidate the metabolic pathways affected by pathological conditions like neurodegeneration. The metabolic disturbances in the 6-hydroxydopamine (6-OHDA) hemiparkinsonian rat model were monitored and the nature and size of these metabolic alterations were analyzed. The results indicate that a unilateral injection of 6-OHDA into the striatum causes metabolic changes that not only affect the injected hemisphere but also the contralateral, non-lesioned side. We could clearly identify specific metabolic pathways that were affected, which were mostly related with oxidative stress and neurotransmission. In addition, a partial metabolic recovery by carrying out an antioxidant treatment with N-acetylcysteine (NAC) was observable.
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