| 1. |
- Fridjonsdottir, Elva, et al.
(författare)
-
Mass spectrometry imaging identifies abnormally elevated brain L-DOPA levels and extrastriatal monoaminergic dysregulation in L-DOPA-induced dyskinesia
- 2021
-
Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 7:2
-
Tidskriftsartikel (refereegranskat)abstract
- L-DOPA treatment for Parkinson's disease frequently leads to dyskinesias, the pathophysiology of which is poorly understood. We used MALDI-MSI to map the distribution of L-DOPA and monoaminergic pathways in brains of dyskinetic and nondyskinetic primates. We report elevated levels of L-DOPA, and its metabolite 3-O-methyldopa, in all measured brain regions of dyskinetic animals and increases in dopamine and metabolites in all regions analyzed except the striatum. In dyskinesia, dopamine levels correlated well with L-DOPA levels in extrastriatal regions, such as hippocampus, amygdala, bed nucleus of the stria terminalis, and cortical areas, but not in the striatum. Our results demonstrate that L-DOPA-induced dyskinesia is linked to a dysregulation of L-DOPA metabolism throughout the brain. The inability of extrastriatal brain areas to regulate the formation of dopamine during L-DOPA treatment introduces the potential of dopamine or even L-DOPA itself to modulate neuronal signaling widely across the brain, resulting in unwanted side effects.
|
|
| 2. |
- Fridjonsdottir, Elva, et al.
(författare)
-
Region-Specific and Age-Dependent Multitarget Effects of Acetylcholinesterase Inhibitor Tacrine on Comprehensive Neurotransmitter Systems
- 2022
-
Ingår i: ACS Chemical Biology. - : American Chemical Society (ACS). - 1554-8929 .- 1554-8937. ; 17:1, s. 147-158
-
Tidskriftsartikel (refereegranskat)abstract
- Regional brain distribution and metabolism of neurotransmitters and their response to drug treatment are fundamentally important for understanding the central effects of neuroactive substances. We used matrix-assisted laser desorption/ionization mass spectrometry imaging in combination with multivariate analysis to visualize in anatomical detail metabolic effects of aging and tacrine-mediated acetylcholinesterase inhibition on comprehensive neurotransmitter systems in multiple mouse brain regions of 12-week-old and 14-month-old mice. We detected age-related increases in 3,4-dihydroxyphenylacetaldehyde and histamine, indicating oxidative stress and aging deficits in astrocytes. Tacrine had a significant impact on the metabolism of neurotransmitters in both age groups; predominantly, there was an increased norepinephrine turnover throughout the brain and decreased 3-methoxy tyramine, a marker for dopamine release, in the striatum. The striatal levels of histamine were only elevated after tacrine administration in the older animals. Our results demonstrated that tacrine is a multitarget and region-specific neuroactive agent, inducing age-specific responses. Although well-studied, the complete mechanisms of the action of tacrine are not fully understood, and the current findings reveal features that may help explain its treatment-related effectiveness and central side effects.
|
|
| 3. |
- He, Yachao, et al.
(författare)
-
Prosaposin maintains lipid homeostasis in dopamine neurons and counteracts experimental parkinsonism in rodents
- 2023
-
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14
-
Tidskriftsartikel (refereegranskat)abstract
- Prosaposin (PSAP) modulates glycosphingolipid metabolism and variants have been linked to Parkinson's disease (PD). Here, we find altered PSAP levels in the plasma, CSF and post-mortem brain of PD patients. Altered plasma and CSF PSAP levels correlatewith PD-relatedmotor impairments. Dopaminergic PSAP-deficient (cPSAP(DAT)) mice display hypolocomotion and depression/anxiety-like symptoms with mildly impaired dopaminergic neurotransmission, while serotonergic PSAP-deficient (cPSAP(SERT)) mice behave normally. Spatial lipidomics revealed an accumulation of highly unsaturated and shortened lipids and reduction of sphingolipids throughout the brains of cPSAP(DAT) mice. The overexpression of alpha-synuclein via AAV lead to more severe dopaminergic degeneration and higher p-Ser129 alpha-synuclein levels in cPSAP(DAT) mice compared to WT mice. Overexpression of PSAP via AAV and encapsulated cell biodelivery protected against 6-OHDA and alpha-synuclein toxicity in wild-type rodents. Thus, these findings suggest PSAP may maintain dopaminergic lipid homeostasis, which is dysregulated in PD, and counteract experimental parkinsonism.
|
|
| 4. |
- Hulme, Heather, et al.
(författare)
-
Simultaneous mass spectrometry imaging of multiple neuropeptides in the brain and alterations induced by experimental parkinsonism and L-DOPA therapy
- 2020
-
Ingår i: Neurobiology of Disease. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 0969-9961 .- 1095-953X. ; 137
-
Tidskriftsartikel (refereegranskat)abstract
- Neuropeptides are important signalling molecules in the brain and alterations in their expression levels have been linked to neurological disorders such as Parkinson's disease. It is challenging to map neuropeptide changes across and within brain regions because of their low in vivo concentrations and complex post-translational processing. Consequently, the role of neuropeptides in Parkinson's disease is not well understood. Thus, we have developed and evaluated a method to image multiple neuropeptides simultaneously in both rat and primate brain tissue sections by matrix-assisted laser desorption/ionisation mass spectrometry imaging at high lateral resolution. Using a unilateral 6-hydroxydopamine rat model of Parkinson's disease, we imaged changes in enkephalins, dynorphins, tachykinins and neurotensin associated with the dopaminergic denervation and L-DOPA treatment in multiple brain regions. L-DOPA administration significantly affected neuropeptides in the globus pallidus, while neuropeptides in the caudate-putamen were mostly affected by dopamine depletion. Using high lateral resolution imaging, we observed an increase of neurotensin in the dorsal sub-region of the globus pallidus after dopamine depletion. This study highlights the capacity of mass spectrometry imaging to elucidate the dynamics of neuropeptide signalling during Parkinson's disease and its treatment.
|
|
| 5. |
- Kaya, Ibrahim, et al.
(författare)
-
On-Tissue Chemical Derivatization for Comprehensive Mapping of Brain Carboxyl and Aldehyde Metabolites by MALDI-MS Imaging
- 2023
-
Ingår i: Journal of the American Society for Mass Spectrometry. - : American Chemical Society (ACS). - 1044-0305 .- 1879-1123. ; 34:5, s. 836-846
-
Tidskriftsartikel (refereegranskat)abstract
- The visualization of small metabolites by MALDI mass spectrometry imaging in brain tissue sections is challenging due to low detection sensitivity and high background interference. We present an on-tissue chemical derivatization MALDI mass spectrometry imaging approach for the comprehensive mapping of carboxyls and aldehydes in brain tissue sections. In this approach, the AMPP (1-(4-(aminomethyl)phenyl)pyridin-1-ium chloride) derivatization reagent is used for the covalent charge-tagging of molecules containing carboxylic acid (in the presence of peptide coupling reagents) and aldehydes. This includes free fatty acids and the associated metabolites, fatty aldehydes, dipeptides, neurotoxic reactive aldehydes, amino acids, neurotransmitters and associated metabolites, as well as tricarboxylic acid cycle metabolites. We performed sensitive ultrahigh mass resolution MALDI-MS detection and imaging of various carboxyl-and aldehyde containing endogenous metabolites simultaneously in rodent brain tissue sections. We verified the AMPP-derivatized metabolites by tandem MS for structural elucidation. This approach allowed us to image numerous aldehydes and carboxyls, including certain metabolites which had been undetectable in brain tissue sections. We also demonstrated the application of on-tissue derivatization to carboxyls and aldehydes in coronal brain tissue sections of a nonhuman primate Parkinson's disease model. Our methodology provides a powerful tool for the sensitive, simultaneous spatial molecular imaging of numerous aldehydes and carboxylic acids during pathological states, including neurodegeneration, in brain tissue.
|
|
| 6. |
- Kaya, Ibrahim, et al.
(författare)
-
Spatial lipidomics reveals brain region-specific changes of sulfatides in an experimental MPTP Parkinson's disease primate model
- 2023
-
Ingår i: npj Parkinson's Disease. - : Springer Nature. - 2373-8057. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- Metabolism of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) to the neurotoxin MPP+ in the brain causes permanent Parkinson's disease-like symptoms by destroying dopaminergic neurons in the pars compacta of the substantia nigra in humans and non-human primates. However, the complete molecular pathology underlying MPTP-induced parkinsonism remains poorly understood. We used dual polarity matrix-assisted laser desorption/ionization mass spectrometry imaging to thoroughly image numerous glycerophospholipids and sphingolipids in coronal brain tissue sections of MPTP-lesioned and control non-human primate brains (Macaca mulatta). The results revealed specific distributions of several sulfatide lipid molecules based on chain-length, number of double bonds, and importantly, hydroxylation stage. More specifically, certain long-chain hydroxylated sulfatides with polyunsaturated chains in the molecular structure were depleted within motor-related brain regions in the MPTP-lesioned animals, e.g., external and internal segments of globus pallidus and substantia nigra pars reticulata. In contrast, certain long-chain non-hydroxylated sulfatides were found to be elevated within the same brain regions. These findings demonstrate region-specific dysregulation of sulfatide metabolism within the MPTP-lesioned macaque brain. The depletion of long-chain hydroxylated sulfatides in the MPTP-induced pathology indicates oxidative stress and oligodendrocyte/myelin damage within the pathologically relevant brain regions. Hence, the presented findings improve our current understanding of the molecular pathology of MPTP-induced parkinsonism within primate brains, and provide a basis for further research regarding the role of dysregulated sulfatide metabolism in PD.
|
|
| 7. |
- Källback, Patrik, et al.
(författare)
-
Cross-validated Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging Quantitation Protocol for a Pharmaceutical Drug and Its Drug-Target Effects in the Brain Using Time-of-Flight and Fourier Transform Ion Cyclotron Resonance Analyzers
- 2020
-
Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 92:21, s. 14676-14684
-
Tidskriftsartikel (refereegranskat)abstract
- Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is an established tool in drug development, which enables visualization of drugs and drug metabolites at spatial localizations in tissue sections from different organs. However, robust and accurate quantitation by MALDI-MSI still remains a challenge. We present a quantitative MALDI-MSI method using two instruments with different types of mass analyzers, i.e., time-of-flight (TOF) and Fourier transform ion cyclotron resonance (FTICR) MS, for mapping levels of the in vivo-administered drug citalopram, a selective serotonin reuptake inhibitor, in mouse brain tissue sections. Six different methods for applying calibration standards and an internal standard were evaluated. The optimized method was validated according to authorities' guidelines and requirements, including selectivity, accuracy, precision, recovery, calibration curve, sensitivity, reproducibility, and stability parameters. We showed that applying a dilution series of calibration standards followed by a homogeneously applied, stable, isotopically labeled standard for normalization and a matrix on top of the tissue section yielded similar results to those from the reference method using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The validation results were within specified limits and the brain concentrations for TOF MS (51.1 +/- 4.4 pmol/mg) and FTICR MS (56.9 +/- 6.0 pmol/mg) did not significantly differ from those of the cross-validated LC-MS/MS method (55.0 +/- 4.9 pmol/mg). The effect of in vivo citalopram administration on the serotonin neurotransmitter system was studied in the hippocampus, a brain region that is the principal target of the serotonergic afferents along with the limbic system, and it was shown that serotonin was significantly increased (2-fold), but its metabolite 5-hydroxyindoleacetic acid was not. This study makes a substantial step toward establishing MALDI-MSI as a fully quantitative validated method.
|
|
| 8. |
- Madeira, Alexandra, et al.
(författare)
-
Caveolin-1 interacts with alpha-synuclein and mediates toxic actions of cellular alpha-synuclein overexpression
- 2011
-
Ingår i: Neurochemistry International. - : Elsevier BV. - 0197-0186 .- 1872-9754. ; 59:2, s. 280-289
-
Tidskriftsartikel (refereegranskat)abstract
- Caveolin-1 (Cav-1) is a transmembrane protein which clusters proteins and lipids at the cell membrane into a subclass of lipid rafts named caveolae. To increase our understanding about putative functions of Cav-1 in neuronal cells, we used mouse brain extracts and a novel technology coupling surface plasmon resonance to mass spectrometry to find binding partners to Cav-1. An interaction between Cav-1 and alpha-synclein was found and confirmed in reciprocal pulldown experiments. Genetic overexpression of alpha-synclein in mouse neuroblastoma Neuro2A cells (N2A) expectedly decreased cell survival, but also significantly increased the levels of Cav-1. Furthermore, si-RNA-mediated knockdown of Cav-1 counteracted cell death induced by overexpression of alpha-synuclein. We also used an inhibitor of proteasome (MG132) to induce cell death in a Parkinson's disease context. Cav-1 knockdown had no effect on cell death induced by MG132. Conversely, treating the cells with mevastatin, an inhibitor of cholesterol synthesis, inhibits cell death induced by MG132, but not by alpha synuclein overexpression. It can be concluded that Cav-1 may play a functional role in neuronal cells by virtue of its physical interaction with alpha-synuclein and regulate alpha synuclein-mediated actions on cell death, processes known to be involved in synucleinopathies including Parkinson's disease.
|
|
| 9. |
- Madeira, Alexandra, et al.
(författare)
-
Coupling surface plasmon resonance to mass spectrometry to discover novel protein-protein interactions
- 2009
-
Ingår i: Nature Protocols. - : Springer Science and Business Media LLC. - 1754-2189 .- 1750-2799. ; 4:7, s. 1023-1037
-
Tidskriftsartikel (refereegranskat)abstract
- The elucidation of protein-protein interaction networks is a crucial task in the postgenomic era. In this protocol, we describe our approach to discover protein-protein interactions using the surface plasmon resonance technique coupled to mass spectrometry ( MS). A peptide or a protein is immobilized on a sensor chip and then exposed to brain extracts injected through the surface of the chip by a microfluidic system. The interactions between the immobilized ligand and the extracts can be monitored in real time. Proteins interacting with the peptide/protein are recovered, trypsinated and identified using MS. The data obtained are searched against a sequence database using the Mascot 2.1 software. Control experiments using blank sensor chips and/or randomized peptides are carried out to exclude nonspecific interactors. The protocol can be carried out in < 3 days. Other methods, such as yeast two-hybrid systems or pull-down approaches followed by MS, are widely used to screen protein-protein interactions. However, as the yeast two-hybrid system requires protein interactions in the nucleus of yeast, proteins that are abundant in other compartments may not be detected. Pull-down approaches based on immunoprecipitation can be used to study endogenous proteins but they require specific antibodies. The protocol presented here does not require the specific labeling or modification of proteins.
|
|
| 10. |
- Madeira, Alexandra, et al.
(författare)
-
Identification of protein-protein interactions by surface plasmon resonance followed by mass spectrometry
- 2011
-
Ingår i: Current protocols in protein science. - Hoboken, NJ, USA : John Wiley & Sons, Inc.. - 1934-3663. ; Suppl. 65, s. 19.21.1-19.21.9
-
Tidskriftsartikel (refereegranskat)abstract
- Elucidation of the function and meaning of the protein networks can be useful in the understanding of many pathological processes and the identification of new therapeutic targets. This unit describes an approach to discover protein-protein interactions by coupling surface plasmon resonance to mass spectrometry. Briefly, a protein is covalently bound to a sensor chip, which is then exposed to brain extracts injected over the surface via a microfluidic system. This allows the monitoring in real-time of the interactions between the immobilized ligand and the extracts. Interacting proteins from the extracts are then recovered, trypsinized, and identified using mass spectrometry. The data obtained are searched against a sequence database using the Mascot software. To exclude nonspecific interactors, control experiments using blank sensor chips, and/or randomized peptides, are performed. The protocol presented here does not require specific labeling or modification of proteins and can be performed in <4 days.
|
|
