| 1. |
- Michno, Wojciech, 1992, et al.
(författare)
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GM1 locates to mature amyloid structures implicating a prominent role for glycolipid-protein interactions in Alzheimer pathology
- 2019
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Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : Elsevier BV. - 1878-1454 .- 1570-9639. ; 1867:5, s. 458-467
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Tidskriftsartikel (refereegranskat)abstract
- While the molecular mechanisms underlying Alzheimer's disease (AD) remain largely unknown, abnormal accumulation and deposition of beta amyloid (AD) peptides into plaques has been proposed as a critical pathological process driving disease progression. Over the last years, neuronal lipid species have been implicated in biological mechanisms underlying amyloid plaque pathology. While these processes comprise genetic features along with lipid signaling as well as direct chemical interaction of lipid species with A beta mono- and oligomers, more efforts are needed to spatially delineate the exact lipid-A beta plaque interactions in the brain. Chemical imaging using mass spectrometry (MS) allows to probe the spatial distribution of lipids and peptides in complex biological tissues comprehensively and at high molecular specificity. As different imaging mass spectrometry (IMS) modalities provide comprehensive molecular and spatial information, we here describe a multimodal ToF-SIMS- and MALDI-based IMS strategy for probing lipid and A beta peptide changes in a transgenic mouse model of AD (tgAPP(ArcSwe)). Both techniques identified a general AD-associated depletion of cortical sulfatides, while multimodal MALDI IMS revealed plaque specific lipid as well as A beta peptide isoforms. In addition, MALDI IMS analysis revealed chemical features associated with morphological heterogeneity of individual A beta deposits. Here, an altered GM1 to GM2/GM3 ganglioside metabolism was observed in the diffuse periphery of plaques but not in the core region. This was accompanied by an enrichment of A beta 1-40arc peptide at the core of these deposits. Finally, a localization of arachidonic acid (AA) conjugated phosphatidylinositols (PI) and their corresponding degradation product, lysophosphatidylinositols (LPI) to the periphery of A beta plaques was observed, indicating site specific macrophage activation and ganglioside processing.
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| 2. |
- Michno, Wojciech, 1992, et al.
(författare)
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Molecular imaging mass spectrometry for probing protein dynamics in neurodegenerative disease pathology
- 2019
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 151:4, s. 488-506
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Forskningsöversikt (refereegranskat)abstract
- Recent advances in the understanding of basic pathological mechanisms in various neurological diseases depend directly on the development of novel bioanalytical technologies that allow sensitive and specific chemical imaging at high resolution in cells and tissues. Mass spectrometry-based molecular imaging (IMS) has gained increasing popularity in biomedical research for mapping the spatial distribution of molecular species in situ. The technology allows for comprehensive, untargeted delineation of in situ distribution profiles of metabolites, lipids, peptides and proteins. A major advantage of IMS over conventional histochemical techniques is its superior molecular specificity. Imaging mass spectrometry has therefore great potential for probing molecular regulations in CNS-derived tissues and cells for understanding neurodegenerative disease mechanism. The goal of this review is to familiarize the reader with the experimental workflow, instrumental developments and methodological challenges as well as to give a concise overview of the major advances and recent developments and applications of IMS-based protein and peptide profiling with particular focus on neurodegenerative diseases. This article is part of the Special Issue “Proteomics”. (Figure presented.).
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| 3. |
- Sandin, Linnea, et al.
(författare)
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Beneficial effects of increased lysozyme levels in Alzheimer’s disease modelled in Drosophila melanogaster
- 2016
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 283:19, s. 3508-3522
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Tidskriftsartikel (refereegranskat)abstract
- Genetic polymorphisms of immune genes that associate with higher risk to develop Alzheimer’s disease (AD) have led to an increased research interest on the involvement of the immune system in AD pathogenesis. A link between amyloid pathology and immune gene expression was suggested in a genome-wide gene expression study of transgenic amyloid mouse models. In this study, the gene expression of lysozyme, a major player in the innate immune system, was found to be increased in a comparable pattern as the amyloid pathology developed in transgenic mouse models of AD. A similar pattern was seen at protein levels of lysozyme in human AD brain and CSF, but this lysozyme pattern was not seen in a tau transgenic mouse model. Lysozyme was demonstrated to be beneficial for different Drosophila melanogaster models of AD. In flies that expressed Aβ1-42 or AβPP together with BACE1 in the eyes, the rough eye phenotype indicative of toxicity was completely rescued by coexpression of lysozyme. In Drosophila flies bearing the Aβ1-42 variant with the Arctic gene mutation, lysozyme increased the fly survival and decreased locomotor dysfunction dose dependently. An interaction between lysozyme and Aβ1-42 in the Drosophila eye was discovered. We propose that the increased levels of lysozyme, seen in mouse models of AD and in human AD cases, were triggered by Aβ1-42 and caused a beneficial effect by binding of lysozyme to toxic species of Aβ1-42, which prevented these from exerting their toxic effects. These results emphasize the possibility of lysozyme as biomarker and therapeutic target for AD.
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| 4. |
- Michno, Wojciech, 1992, et al.
(författare)
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Multimodal Chemical Imaging of Amyloid Plaque Polymorphism Reveals A beta Aggregation Dependent Anionic Lipid Accumulations and Metabolism
- 2018
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 90:13, s. 8130-8138
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid plaque formation constitutes one of the main pathological hallmarks of Alzheimer's disease (AD) and is suggested to be a critical factor driving disease pathogenesis. Interestingly, in patients that display amyloid pathology but remain cognitively normal, A beta deposits are predominantly of diffuse morphology suggesting that cored plaque formation is primarily associated with cognitive deterioration and AD pathogenesis. Little is known about the molecular mechanism responsible for conversion of monomeric A beta into neurotoxic aggregates and the predominantly cored deposits observed in AD. The structural diversity among A beta plaques, including cored/compact- and diffuse, may be linked to their distinct A beta profile and other chemical species including neuronal lipids. We developed a novel, chemical imaging paradigm combining matrix assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) and fluorescent amyloid staining. This multimodal imaging approach was used to probe the lipid chemistry associated with structural plaque heterogeneity in transgenic AD mice (tgAPP(Swe)) and was correlated to A beta profiles determined by subsequent laser microdissection and immunoprecipitation-mass spectrometry. Multivariate image analysis revealed an inverse localization of ceramides and their matching metabolites to diffuse and cored structures within single plaques, respectively. Moreover, phosphatidylinositols implicated in AD pathogenesis, were found to localize to the diffuse A beta structures and correlate with A beta 1-42. Further, lysophospholipids implicated in neuroinflammation were increased in all A beta deposits. The results support previous clinical findings on the importance of lipid disturbances in AD pathophysiology and associated sphingolipid processing. These data highlight the potential of multimodal imaging as a powerful technology to probe neuropathological mechanisms.
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| 5. |
- Karikari, Thomas, et al.
(författare)
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An extensive plasmid library to prepare tau protein variants and study their functional biochemistry.
- 2020
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Ingår i: ACS chemical neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 11:19
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Tidskriftsartikel (refereegranskat)abstract
- Tau neurofibrillary tangles are key pathological features of Alzheimer's disease and other tauopathies. Recombinant protein technology is vital for studying the structure and function of tau in physiology and aggregation in pathophysiology. However, open-source and well-characterized plasmids for efficiently expressing and purifying different tau variants are lacking. We generated 44 sequence-verified plasmids including those encoding full length (FL) tau-441, its four-repeat microtubule-binding (K18) fragment, and their respective selected familial pathological variants (N279K, V337M, P301L, C291R and S356T). Moreover, plasmids for expressing single (C291A), double (C291A/C322A) and triple (C291A/C322A/I260C) cysteine-modified variants were generated to study alterations in cysteine content and locations. Furthermore, protocols for producing representative tau forms were developed. We produced and characterized the aggregation behavior of the triple cysteine-modified tau-K18, often used in real-time cell internalization and aggregation studies because it can be fluorescently labeled on a cysteine outside the microtubule-binding core. Similar to the wild type (WT), triple cysteine-modified tau-K18 aggregated by progressive -sheet enrichment, albeit at a slower rate. On prolonged incubation, cysteine-modified K18 formed paired helical filaments similar to those in Alzheimer's disease, sharing morphological phenotypes with WT tau-K18 filaments. Nonetheless, cysteine-modified tau-K18 filaments were significantly shorter (p=0.002) and mostly wider than WT filaments, explainable by their different principal filament elongation pathways: vertical (end-to-end) and lateral growth for WT and cysteine-modified respectively. Cysteine rearrangement may therefore induce filament polymorphism. Together, the plasmid library, the protein production methods, and the new insights into cysteine-dependent aggregation, should facilitate further studies and the design of anti-aggregation agents.
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| 6. |
- Mattila, O. S., et al.
(författare)
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Ultra-Early Differential Diagnosis of Acute Cerebral Ischemia and Hemorrhagic Stroke by Measuring the Prehospital Release Rate of GFAP
- 2021
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 67:10, s. 1361-1372
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Plasma glial fibrillary acidic protein (GFAP) and tau are promising markers for differentiating acute cerebral ischemia (ACI) and hemorrhagic stroke (HS), but their prehospital dynamics and usefulness are unknown. METHODS: We performed ultra-sensitivite single-molecule array (Simoa((R))) measurements of plasma GFAP and total tau in a stroke code patient cohort with cardinal stroke symptoms [National Institutes of Health Stroke Scale (NIHSS) >= 3]. Sequential sampling included 2 ultra-early samples, and a follow-up sample on the next morning. RESULTS: We included 272 cases (203 ACI, 60 HS, and 9 stroke mimics). Median (IQR) last-known-well to sampling time was 53 (35-90) minutes for initial prehospital samples, 90 (67-130) minutes for secondary acute samples, and 21 (16-24) hours for next morning samples. Plasma GFAP was significantly higher in patients with HS than ACI (P<0.001 for <1hour and <3hour prehospital samples, and <3hour secondary samples), while total tau showed no intergroup difference. The prehospital GFAP release rate (pg/mL/minute) occurring between the 2 very early samples was significantly higher in patients with HS than ACI [2.4 (0.6-14.1)] versus 0.3 (-0.3-0.9)pg/mL/minute, P<0.001. For cases with <3hour prehospital sampling (ACI n=178, HS n=59), a combined rule (prehospital GFAP >410pg/mL, or prehospital GFAP 90-410pg/mL together with GFAP release >0.6pg/mL/minute) enabled ruling out HS with high certainty (NPV 98.4%) in 68% of patients with ACI (sensitivity for HS 96.6%, specificity 68%, PPV 50%). CONCLUSIONS: In comparison to single-point measurement, monitoring the prehospital GFAP release rate improves ultra-early differentiation of stroke subtypes. With serial measurement GFAP has potential to improve future prehospital stroke diagnostics.
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| 7. |
- Moore, S., et al.
(författare)
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APP Metabolism Regulates Tau Proteostasis in Human Cerebral Cortex Neurons
- 2015
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 11:5, s. 689-696
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Tidskriftsartikel (refereegranskat)abstract
- Accumulation of A beta peptide fragments of the APP protein and neurofibrillary tangles of the microtubule-associated protein tau are the cellular hallmarks of Alzheimer's disease (AD). To investigate the relationship between APP metabolism and tau protein levels and phosphorylation, we studied human-stem-cell-derived forebrain neurons with genetic forms of AD, all of which increase the release of pathogenic A beta peptides. We identified marked increases in intracellular tau in genetic forms of AD that either mutated APP or increased its dosage, suggesting that APP metabolism is coupled to changes in tau proteostasis. Manipulating APP metabolism by beta-secretase and gamma-secretase inhibition, as well as gamma-secretase modulation, results in specific increases and decreases in tau protein levels. These data demonstrate that APP metabolism regulates tau proteostasis and suggest that the relationship between APP processing and tau is not mediated solely through extracellular A beta signaling to neurons.
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| 8. |
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| 9. |
- Bellaver, B., et al.
(författare)
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Astrocyte reactivity influences amyloid-beta effects on tau pathology in preclinical Alzheimer's disease
- 2023
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Ingår i: Nature Medicine. - 1078-8956. ; 29:7, s. 1775-
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Tidskriftsartikel (refereegranskat)abstract
- Cross-sectional and longitudinal analyses of tau pathology in preclinical Alzheimer's disease reveal that tau tangles accumulate as a function of amyloid-beta burden only in individuals positive for an astrocyte reactivity biomarker. An unresolved question for the understanding of Alzheimer's disease (AD) pathophysiology is why a significant percentage of amyloid-beta (A beta)-positive cognitively unimpaired (CU) individuals do not develop detectable downstream tau pathology and, consequently, clinical deterioration. In vitro evidence suggests that reactive astrocytes unleash A beta effects in pathological tau phosphorylation. Here, in a biomarker study across three cohorts (n = 1,016), we tested whether astrocyte reactivity modulates the association of A beta with tau phosphorylation in CU individuals. We found that A beta was associated with increased plasma phosphorylated tau only in individuals positive for astrocyte reactivity (Ast(+)). Cross-sectional and longitudinal tau-positron emission tomography analyses revealed an AD-like pattern of tau tangle accumulation as a function of A beta only in CU Ast(+) individuals. Our findings suggest astrocyte reactivity as an important upstream event linking A beta with initial tau pathology, which may have implications for the biological definition of preclinical AD and for selecting CU individuals for clinical trials.
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| 10. |
- Betancor, M., et al.
(författare)
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Neurogranin and Neurofilament Light Chain as Preclinical Biomarkers in Scrapie
- 2022
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1422-0067. ; 23:13
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Tidskriftsartikel (refereegranskat)abstract
- Prion diseases are diagnosed in the symptomatic stage, when the neuronal damage is spread throughout the central nervous system (CNS). The assessment of biological features that allow the detection of asymptomatic cases is needed, and, in this context, scrapie, where pre-symptomatic infected animals can be detected through rectal biopsy, becomes a good study model. Neurogranin (Ng) and neurofilament light chain (NfL) are proteins that reflect synaptic and axonal damage and have been studied as cerebrospinal fluid (CSF) biomarkers in different neurodegenerative disorders. In this study, we evaluated Ng and NfL both at the protein and transcript levels in the CNS of preclinical and clinical scrapie-affected sheep compared with healthy controls and assessed their levels in ovine CSF. The correlation between these proteins and the main neuropathological events in prion diseases, PrPSc deposition and spongiosis, was also assessed. The results show a decrease in Ng and NfL at the protein and gene expression levels as the disease progresses, and significant changes between the control and preclinical animals. On the contrary, the CSF levels of NfL increased throughout the progression of the disease. Negative correlations between neuropathological markers of prion disease and the concentration of the studied proteins were also found. Although further research is needed, these results suggest that Ng and NfL could act as biomarkers for neurodegeneration onset and intensity in preclinical cases of scrapie.
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