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- Carlred, Louise M, 1985
(författare)
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Detection of Lipids and Proteins on Biological Surfaces using Imaging Mass Spectrometry
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a technique that can be used for imaging the spatial distribution of many different molecules at the same time. It is very sensitive for detection of small biomolecules, such as lipids, whereas larger biomolecules, such as peptides and proteins, cannot be detected as intact entities due to fragmentation. In this work, we have explored an alternative approach for detection of peptides and proteins with ToF-SIMS, using liposomes for labeling the target of interest. In this way, both lipids and proteins can be imaged at the same time, which opens up for the opportunity to investigate lipid-protein interactions. The method has been applied for detection of biomolecules on two different biological surfaces; (1) a model surface containing controlled concentrations of target biomolecules bound to the substrate and (2) brain tissue sections from Alzheimer’s disease transgenic mice. Other techniques, such as fluorescence microscopy and quartz crystal microbalance with dissipation monitoring (QCM-D), have also been used for the characterization of liposomes binding to the surface. Another imaging mass spectrometry technique, matrix-assisted laser desorption/ionization (MALDI), was also employed on mouse brain tissue sections for detection and investigation of amyloid-β deposits, a peptide associated with Alzheimer’s disease. This thesis thus shows how different techniques can be combined for investigation of biomolecules on complex biological surfaces, in order to potentially provide new information about the mechanism of neurodegeneration in Alzheimer’s disease.
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| 2. |
- Carlred, Louise M, 1985, et al.
(författare)
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Imaging of Amyloid-β in Alzheimer’s disease transgenic mouse brains with Time-of-Flight Secondary Ion Mass Spectrometry using Immunoliposomes
- 2016
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Ingår i: Biointerphases. - : American Vacuum Society. - 1559-4106 .- 1934-8630. ; 11:2, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been proven to successfully image different kinds of molecules, especially a variety of lipids, in biological samples. Proteins, however, are difficult to detect as specific entities with this method due to extensive fragmentation. To circumvent this issue, the authors present in this work a method developed for detection of proteins using antibody-conjugated liposomes, so called immunoliposomes, which are able to bind to the specific protein of interest. In combination with the capability of ToF-SIMS to detect native lipids in tissue samples, this method opens up the opportunity to analyze many different biomolecules, both lipids and proteins, at the same time, with high spatial resolution. The method has been applied to detect and image the distribution of amyloid-β (Aβ), a biologically relevant peptide in Alzheimer's disease (AD), in transgenic mouse braintissue. To ensure specific binding, the immunoliposome binding was verified on a model surface using quartz crystal microbalance with dissipation monitoring. The immunoliposome binding was also investigated on tissue sections with fluorescence microscopy, and compared with conventional immunohistochemistry using primary and secondary antibodies, demonstrating specific binding to Aβ. Using ToF-SIMS imaging, several endogenous lipids, such as cholesterol and sulfatides, were also detected in parallel with the immunoliposome-labeled Aβ deposits, which is an advantage compared to fluorescence microscopy. This method can thus potentially provide further information about lipid–protein interactions, which is important to understand the mechanisms of neurodegeneration in AD.
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| 3. |
- Carlred, Louise M, 1985, et al.
(författare)
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Probing Amyloid-β Pathology in transgenic Alzheimer's disease (tgArcSwe) mice using MALDI Imaging Mass Spectrometry
- 2016
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Ingår i: Journal of neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 138:3, s. 469-478
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Tidskriftsartikel (refereegranskat)abstract
- The pathological mechanisms underlying Alzheimer's disease (AD) are still not understood. The disease pathology is characterized by accumulation and aggregation of amyloid-β (Aβ) peptides into extracellular plaques, however the factors that promote neurotoxic Aβ aggregation remain elusive. Imaging mass spectrometry (IMS) is a powerful technique to comprehensively elucidate the spatial distribution patterns of lipids, peptides and proteins in biological tissues. In the present study, matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) based imaging was used to study Aβ deposition in transgenic mouse brain tissue and to elucidate the plaque associated chemical microenvironment. The imaging experiments were performed in brain sections of transgenic Alzheimer's disease mice carrying the Arctic and Swedish mutation of amyloid-beta precursor protein (tgArcSwe). Multivariate image analysis was used to interrogate the IMS data for identifying pathologically relevant, anatomical features based on their chemical identity. This include cortical and hippocampal Aβ deposits, whose amyloid peptide content was further verified using immunohistochemistry and laser micro dissection followed by MALDI MS analysis. Subsequent statistical analysis on spectral data of regions of interest (ROI) revealed brain region specific differences in Aβ peptide aggregation. Moreover, other plaque associated protein species were identified including macrophage migration inhibitory factor (MIF) suggesting neuroinflammatory processes and glial cell reactivity to be involved in AD pathology. The presented data further highlight the potential of IMS as powerful approach in neuropathology.
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