Glycolipidomics of human cerebellum in development and aging by ion mobility tandem mass spectrometry

In this study ion mobility separation (IMS) mass spectrometry (MS) was for the first time introduced in human cerebellum ganglioside research. The work was focused on a comprehensive mapping and structural characterization of human cerebellar gangliosides and determination of the specific changes induced in their expression by brain development and aging. We have carried out a comparative IMS MS mapping of the native ganglioside mixtures extracted from fetal cerebellum in the second trimester of pregnancy vs. near-term fetus vs. aged cerebellum, followed by IMS CID MS/MS fragmentation analysis

Advanced mass spectrometry methods for the determination of gangliosides structure and functional interactions

To address the issues of high biological relevance of gangliosides (GGs), mass spectrometry (MS) has lately become a method of choice due to its capability to detect minor species in complex mixtures and the unsurpassed sensitivity. GGs are localized in the cellular membrane, with the ceramide (Cer) rooted in the lipid bilayer and the oligosaccharide chain protruding freely outside the cell, acting as a receptor [1,2]. Here, a complex mixture of GGs extracted from adult human brain was first characterized by MS for a thorough mapping and a detailed structural characterization, and lately, the complex GG mixture was submitted to an interaction assay with the B subunit monomers of cholera toxin (Ctb5). Aliquots of the reaction products were collected after 10 and 30 min and also after 60 min and submitted to MS analysis. Multistage fragmentation by electron transfer dissociation (ETD) and collisioninduced dissociation (CID) completed the assay and provided solid data on the noncovalent biding site at the monomer level

Characterization of hybrid chondroitin/dermatan sulfate octasaccharide domains in human brain by ion mobility tandem mass spectrometry

We report here on the introduction of a rapid, highly sensitive and reliable approach in a single run, based on ion mobility separation (IMS), high resolution and tandem MS (MS/MS) by collision-induced dissociation (CID) for compositional and structural elucidation of neural chondroitin sulfate (CS) and dermatan sulfate (DS) domains, which implies the determination of the epimerization and the sulfation code of regular and irregular structures. By IMS MS and CID MS/MS, we were able to characterize in details CS/DS octasaccharides from brain obtained after CS/DS chain depolymerization by chondroitin B lyase and to detect sequences that were never found before in the octasaccharide domains of the investigated CS/DS brain fraction

Gangliosides as Biomarkers of Human Brain Diseases: Trends in Discovery and Characterization by High-Performance Mass Spectrometry

Gangliosides are effective biochemical markers of brain pathologies, being also in the focus of research as potential therapeutic targets. Accurate brain ganglioside mapping is an essential requirement for correlating the specificity of their composition with a certain pathological state and establishing a well-defined set of biomarkers. Among all bioanalytical methods conceived for this purpose, mass spectrometry (MS) has developed into one of the most valuable, due to the wealth and consistency of structural information provided. In this context, the present article reviews the achievements of MS in discovery and structural analysis of gangliosides associated with severe brain pathologies. The first part is dedicated to the contributions of MS in the assessment of ganglioside composition and role in the specific neurodegenerative disorders: Alzheimer’s and Parkinson’s diseases. A large subsequent section is devoted to cephalic disorders (CD), with an emphasis on the MS of gangliosides in anencephaly, the most common and severe disease in the CD spectrum. The last part is focused on the major accomplishments of MS-based methods in the discovery of ganglioside species, which are associated with primary and secondary brain tumors and may either facilitate an early diagnosis or represent target molecules for immunotherapy oriented against brain cancers

Identification and Structural Characterization of Novel Chondroitin/Dermatan Sulfate Hexassacharide Domains in Human Decorin by Ion Mobility Tandem Mass Spectrometry

Chondroitin sulfate (CS) and dermatan sulfate (DS) are found in nature linked to proteoglycans, most often as hybrid CS/DS chains. In the extracellular matrix, where they are highly expressed, CS/DS are involved in fundamental processes and various pathologies. The structural diversity of CS/DS domains gave rise to efforts for the development of efficient analytical methods, among which is mass spectrometry (MS), one of the most resourceful techniques for the identification of novel species and their structure elucidation. In this context, we report here on the introduction of a fast, sensitive, and reliable approach based on ion mobility separation (IMS) MS and MS/MS by collision-induced dissociation (CID), for the profiling and structural analysis of CS/DS hexasaccharide domains in human embryonic kidney HEK293 cells decorin (DCN), obtained after CS/DS chain releasing by β-elimination, depolymerization using chondroitin AC I lyase, and fractionation by size-exclusion chromatography. By IMS MS, we were able to find novel CS/DS species, i.e., under- and oversulfated hexasaccharide domains in the released CS/DS chain. In the last stage of analysis, the optimized IMS CID MS/MS provided a series of diagnostic fragment ions crucial for the characterization of the misregulations, which occurred in the sulfation code of the trisulfated-4,5-Δ-GlcAGalNAc[IdoAGalNAc]2 sequence, due to the unusual sulfation sites

Gangliosidome of a Human Hippocampus in Temporal Lobe Epilepsy Resolved by High-Resolution Tandem Mass Spectrometry

In this study, we developed a high-resolution tandem mass spectrometry (HR MS) approach to assess presumed changes in gangliosidome of a human hippocampus affected by temporal lobe epilepsy (TLE) in comparison with a normal hippocampus. Gangliosides, membrane glycolipids, are particularly diverse and abundant in the human brain, and participate in ion transport and modulation of neuronal excitability. Changes in structural ganglioside pattern potentially linked to TLE molecular pathogenesis have not been explored in detail. Aiming to characterize TLE-specific gangliosidome, we analyzed the native gangliosides purified from a human hippocampal tissue sample affected by TLE and a control hippocampus using HR MS. Marked differences of ganglioside expression were shown in TLE vs. control, particularly with respect to the sialylation degree of components, discovered as a characteristic feature of TLE. Another major finding is the occurrence of tetrasialofucogangliosides in TLE and species modified by either O-acetylation or CH3COO−. Structural analysis by higher-energy collisional dissociation (HCD) MS/MS gave rise to fragmentation patterns implying that the GQ1b (d18:1/18:0) isomer is specifically associated with TLE. Further investigation in a larger sample is needed in order to confirm the discovery of ganglioside structures specifically expressed in human TLE and to provide information on the probable role of gangliosides in the molecular events underlying seizures