TY - JOUR

T1 - Brain proteome profiling implicates the complement and coagulation cascade in multiple system atrophy brain pathology

AU - Rydbirk, Rasmus

AU - Østergaard, Ole

AU - Folke, Jonas

AU - Hempel, Casper

AU - DellaValle, Brian

AU - Andresen, Thomas L.

AU - Løkkegaard, Annemette

AU - Hejl, Anne-Mette

AU - Bode, Matthias

AU - Blaabjerg, Morten

AU - Møller, Mette

AU - Danielsen, Erik H

AU - Salvesen, Lisette

AU - Starhof, Charlotte C

AU - Bech, Sara

AU - Winge, Kristian

AU - Rungby, Jørgen

AU - Pakkenberg, Bente

AU - Brudek, Tomasz

AU - Olsen, Jesper V

AU - Aznar, Susana

N1 - © 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.

PY - 2022

Y1 - 2022

N2 - BACKGROUND: Multiple system atrophy (MSA) is a rare, progressive, neurodegenerative disorder presenting glia pathology. Still, disease etiology and pathophysiology are unknown, but neuro-inflammation and vascular disruption may be contributing factors to the disease progression. Here, we performed an ex vivo deep proteome profiling of the prefrontal cortex of MSA patients to reveal disease-relevant molecular neuropathological processes. Observations were validated in plasma and cerebrospinal fluid (CSF) of novel cross-sectional patient cohorts.METHODS: Brains from 45 MSA patients and 30 normal controls (CTRLs) were included. Brain samples were homogenized and trypsinized for peptide formation and analyzed by high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). Results were supplemented by western blotting, immuno-capture, tissue clearing and 3D imaging, immunohistochemistry and immunofluorescence. Subsequent measurements of glial fibrillary acid protein (GFAP) and neuro-filament light chain (NFL) levels were performed by immunoblotting in plasma of 20 MSA patients and 20 CTRLs. Finally, we performed a proteome profiling of 144 CSF samples from MSA and CTRLs, as well as other parkinsonian disorders. Data were analyzed using relevant parametric and non-parametric two-sample tests or linear regression tests followed by post hoc tests corrected for multiple testing. Additionally, high-throughput bioinformatic analyses were applied.RESULTS: We quantified more than 4,000 proteins across samples and identified 49 differentially expressed proteins with significantly different abundances in MSA patients compared with CTRLs. Pathway analyses showed enrichment of processes related to fibrinolysis and complement cascade activation. Increased fibrinogen subunit β (FGB) protein levels were further verified, and we identified an enriched recognition of FGB by IgGs as well as intra-parenchymal accumulation around blood vessels. We corroborated blood-brain barrier leakage by a significant increase in GFAP and NFL plasma levels in MSA patients that correlated to disease severity and/or duration. Proteome profiling of CSF samples acquired during the disease course, confirmed increased total fibrinogen levels and immune-related components in the soluble fraction of MSA patients. This was also true for the other atypical parkinsonian disorders, dementia with Lewy bodies and progressive supra-nuclear palsy, but not for Parkinson's disease patients.CONCLUSION: Our results implicate activation of the fibrinolytic cascade and immune system in the brain as contributing factors in MSA associated with a more severe disease course.

AB - BACKGROUND: Multiple system atrophy (MSA) is a rare, progressive, neurodegenerative disorder presenting glia pathology. Still, disease etiology and pathophysiology are unknown, but neuro-inflammation and vascular disruption may be contributing factors to the disease progression. Here, we performed an ex vivo deep proteome profiling of the prefrontal cortex of MSA patients to reveal disease-relevant molecular neuropathological processes. Observations were validated in plasma and cerebrospinal fluid (CSF) of novel cross-sectional patient cohorts.METHODS: Brains from 45 MSA patients and 30 normal controls (CTRLs) were included. Brain samples were homogenized and trypsinized for peptide formation and analyzed by high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). Results were supplemented by western blotting, immuno-capture, tissue clearing and 3D imaging, immunohistochemistry and immunofluorescence. Subsequent measurements of glial fibrillary acid protein (GFAP) and neuro-filament light chain (NFL) levels were performed by immunoblotting in plasma of 20 MSA patients and 20 CTRLs. Finally, we performed a proteome profiling of 144 CSF samples from MSA and CTRLs, as well as other parkinsonian disorders. Data were analyzed using relevant parametric and non-parametric two-sample tests or linear regression tests followed by post hoc tests corrected for multiple testing. Additionally, high-throughput bioinformatic analyses were applied.RESULTS: We quantified more than 4,000 proteins across samples and identified 49 differentially expressed proteins with significantly different abundances in MSA patients compared with CTRLs. Pathway analyses showed enrichment of processes related to fibrinolysis and complement cascade activation. Increased fibrinogen subunit β (FGB) protein levels were further verified, and we identified an enriched recognition of FGB by IgGs as well as intra-parenchymal accumulation around blood vessels. We corroborated blood-brain barrier leakage by a significant increase in GFAP and NFL plasma levels in MSA patients that correlated to disease severity and/or duration. Proteome profiling of CSF samples acquired during the disease course, confirmed increased total fibrinogen levels and immune-related components in the soluble fraction of MSA patients. This was also true for the other atypical parkinsonian disorders, dementia with Lewy bodies and progressive supra-nuclear palsy, but not for Parkinson's disease patients.CONCLUSION: Our results implicate activation of the fibrinolytic cascade and immune system in the brain as contributing factors in MSA associated with a more severe disease course.

KW - Brain/metabolism

KW - Chromatography, Liquid

KW - Cross-Sectional Studies

KW - Disease Progression

KW - Fibrinogen/metabolism

KW - Glial Fibrillary Acidic Protein/metabolism

KW - Humans

KW - Multiple System Atrophy/metabolism

KW - Parkinson Disease/metabolism

KW - Parkinsonian Disorders/metabolism

KW - Proteome/metabolism

KW - Tandem Mass Spectrometry

U2 - 10.1007/s00018-022-04378-z

DO - 10.1007/s00018-022-04378-z

M3 - Journal article

C2 - 35657417

VL - 79

JO - Cellular and Molecular Life Sciences

JF - Cellular and Molecular Life Sciences

SN - 1420-682X

IS - 6

M1 - 336

ER -