Chip-based nanoelectrospray mass spectrometry of brain gangliosides

Advances in Mass Spectrometry of Gangliosides Expressed in Brain Cancers

Gangliosides are highly abundant in the human brain where they are involved in major biological events. In brain cancers, alterations of ganglioside pattern occur, some of which being correlated with neoplastic transformation, while others with tumor proliferation. Of all techniques, mass spectrometry (MS) has proven to be one of the most effective in gangliosidomics, due to its ability to characterize heterogeneous mixtures and discover species with biomarker value. This review highlights the most significant achievements of MS in the analysis of gangliosides in human brain cancers. The first part presents the latest state of MS development in the discovery of ganglioside markers in primary brain tumors, with a particular emphasis on the ion mobility separation (IMS) MS and its contribution to the elucidation of the gangliosidome associated with aggressive tumors. The second part is focused on MS of gangliosides in brain metastases, highlighting the ability of matrix-assisted laser desorption/ionization (MALDI)-MS, microfluidics-MS and tandem MS to decipher and structurally characterize species involved in the metastatic process. In the end, several conclusions and perspectives are presented, among which the need for development of reliable software and a user-friendly structural database as a search platform in brain tumor diagnostics.

Electrical Characterization and Analysis of Single Cells and Related Applications

Biological parameters extracted from electrical signals from various body parts have been used for many years to analyze the human body and its behavior. In addition, electrical signals from cancer cell lines, normal cells, and viruses, among others, have been widely used for the detection of various diseases. Single-cell parameters such as cell and cytoplasmic conductivity, relaxation frequency, and membrane capacitance are important. There are many techniques available to characterize biomaterials, such as nanotechnology, microstrip cavity resonance measurement, etc. This article reviews single-cell isolation and sorting techniques, such as the micropipette separation method, separation and sorting system (dual electrophoretic array system), DEPArray sorting system (dielectrophoretic array system), cell selector sorting system, and microfluidic and valve devices, and discusses their respective advantages and disadvantages. Furthermore, it summarizes common single-cell electrical manipulations, such as single-cell amperometry (SCA), electrical impedance sensing (EIS), impedance flow cytometry (IFC), cell-based electrical impedance (CEI), microelectromechanical systems (MEMS), and integrated microelectrode array (IMA). The article also enumerates the application and significance of single-cell electrochemical analysis from the perspectives of CTC liquid biopsy, recombinant adenovirus, tumor cells like lung cancer DTCs (LC-DTCs), and single-cell metabolomics analysis. The paper concludes with a discussion of the current limitations faced by single-cell analysis techniques along with future directions and potential application scenarios.

High-Resolution Tandem Mass Spectrometry Identifies a Particular Ganglioside Pattern in Early Diabetic Kidney Disease of Type 2 Diabetes Mellitus Patients

Considering the valuable information provided by glycosphingolipids as molecular markers and the limited data available for their detection and characterization in patients suffering from Type 2 diabetic kidney disease (DKD), we developed and implemented a superior method based on high-resolution (HR) mass spectrometry (MS) and tandem MS (MS/MS) for the determination of gangliosides in the urine of DKD patients. This study was focused on: (i) testing of the HR MS and MS/MS feasibility and performances in mapping and sequencing of renal gangliosides in Type 2 DM patients; (ii) determination of the changes in the urine gangliosidome of DKD patients in different stages of the disease-normo-, micro-, and macroalbuminuria-in a comparative assay with healthy controls. Due to the high resolution and mass accuracy, the comparative MS screening revealed that the sialylation status of the ganglioside components; their modification by O-acetyl, CH3COO-, O-fucosyl, and O-GalNAc; as well as the composition of the ceramide represent possible markers for early DKD detection, the assessment of disease progression, and follow-up treatment. Moreover, structural investigation by MS/MS demonstrated that GQ1d(d18:1/18:0), GT1α(d18:1/18:0) and GT1b(d18:1/18:0) isomers are associated with macroalbuminuria, meriting further investigation in relation to their role in DKD.

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.

Developments and applications of separation and microfluidics methods coupled to electrospray mass spectrometry in glycomics of nervous system gangliosides

Gangliosides are particularly abundant in the nervous system (NS) where their pattern and structure in a certain milieu or a defined region exhibit a pronounced specificity. Since gangliosides are useful biomarkers for diagnosis of NS ailments, a clear-cut mapping of individual components represents a prerequisite for designing ganglioside-based diagnostic procedures, treatments, or vaccines. These bioclinical aspects and the high diversity of ganglioside species claim for development of specific analytical strategies. This review summarizes the state-of-the-art in the implementation of separation techniques and microfluidics coupled to MS, which have contributed significantly to the advancement of the field. In the first part, the review discusses relevant approaches based on HPLC MS and CE coupled to ESI MS and their applications in the characterization of gangliosides expressed in healthy and diseased NS. A considerable section is dedicated to microfluidics MS and ion mobility separation MS, developed for the study of brain gangliosidome and its changes triggered by various factors, as well as for ganglioside biomarker discovery in neurodegenerative diseases and brain cancer. In the last part of the review, the benefits and perspectives in ganglioside research of these high-performance techniques are presented.

Sustainable Nanosystem Development for Mass Spectrometry

Nowadays, considerable efforts are invested into development of sustainable nanosystems as front end technology for either Electrospray Ionization (ESI) or Matrix-Assisted Laser Desorption/Ionization (MALDI) mass spectrometry (MS). Since their first introduction in MS, nanofluidics demonstrated a high potential to discover novel biopolymer species. These systems confirmed the unique ability to offer structural elucidation of molecular species, which often represent valuable biomarkers of severe diseases. In view of these major advantages of nanofluidics-MS, this chapter reviews the strategies, which allowed a successful development of nanotechnology for MS and the applications in biological and clinical research. The first part will be dedicated to the principles and technical developments of advanced nanosystems for electrospray and MALDI MS. The second part will highlight the most important applications in clinical proteomics and glycomics. Finally, this chapter will emphasize that advanced nanosystems-MS has real perspectives to become a routine method for early diagnosis of severe pathologies.

Structural characterization of gangliosides and glycolipids via ultraviolet photodissociation mass spectrometry

Ultraviolet photodissociation (UVPD) mass spectrometry was used to characterize the structures of amphiphilic glycosphingolipids and gangliosides in comparison to collision induced dissociation (CID) and higher energy collision dissociation (HCD) in a high performance Orbitrap mass spectrometer. UVPD produced the widest array of fragment ions diagnostic for both the ceramide base and oligosaccharide moieties. CID and HCD generated mainly glycosidic B/Y and C/Z cleavages of the oligosaccharides moieties and very few informative fragments related to the hydrophobic ceramide base. Several unique cleavages at the sphingoid base and the fatty acid chain occurred upon UVPD, as well as a wider variety of cross ring cleavages (A/X ions), thus affording differentiation of isobaric gangliosides. An LC-UVPD-MS strategy allowed the elucidation of 27 gangliosides among five different classes.

Fast quantification of amino acids by microchip electrophoresis-mass spectrometry

A fast microchip electrophoresis-nano-electrospray ionization-mass spectrometric method (MCE-nanoESI-MS) was developed for analysis of amino acids in biological samples. A glass/poly(dimethylsiloxane) hybrid microchip with a monolithic nanoESI emitter was used in the platform. The proposed MCE-nanoESI-MS analytical method showed high separation efficiency for amino acids. Baseline separation of an amino acid mixture containing Lys, Arg, Val, Tyr, and Glu was completed within 120 s with theoretical plate numbers of >7,500. The method was applied to study cellular release of excitatory amino acids (i.e., aspartic acid (Asp) and glutamic acid (Glu)) under chemical stimulations. Linear calibration curves were obtained for both Asp and Glu in a concentration range from 1.00 to 150.0 μM. Limits of detection were found to be 0.37 μM for Asp and 0.33 μM for Glu (S/N = 3). Assay repeatability (relative standard deviation, n = 6) was 4.2 and 4.5%, for Asp and Glu at 5.0 μM, respectively. In the study of cellular release, PC-12 nerve cells were incubated with alcohol at various concentrations for 1 h. Both extra- and intracellular levels of Asp and Glu were measured by the proposed method. The results clearly indicated that ethanol promoted the release of both Asp and Glu from the cells.

High resolution mass spectrometric characterization of amino linked oligosaccharides — a preliminary study

In this study maltose, maltotriose and maltotetraose were for the first time, coupled to 4,4′-methylenedianiline (MDA). The aim of this preliminary work was to test the feasibility of oligo- and polysaccharide coupling to MDA and the characterization of the coupling products by high resolution mass spectrometry (MS). (+) nanoESI in combination with a quadrupole time of flight (QTOF) MS in full scan (MS) and MS/MS was optimized first on underivatized maltose, maltotriose and maltotetraose. The optimal screening and sequencing conditions were further applied to the MDA-functionalized oligosaccharides. The obtained results revealed a straightforward MS detection of the functionalized oligomers, high sequence coverage and a fragmentation pathway with the formation of B and Y ions as well as the complementary C and Z ions along with a typical cleavage of the aglycon. We consider that this methodology is fully applicable also to polydisperse mixtures of long chain polysaccharides, which due to the large number of components and their size require a systematic method of development and testing.

Mass Spectrometry of Gangliosides from Human Sensory and Motor Cortex

Sialylated glycosphingolipids, known as gangliosides, are highly expressed in the central nervous system exhibiting region-specific composition in correlation to the specialised functions of particular brain regions. In the present study high resolution tandem mass spectrometry on a quadrupole time-of-flight instrument with nanoelectrospray was optimised and applied for the first comparative assessment of the ganglioside profile in single specimens of adult human motor and somatosensory cortex. In the second stage, the structural analysis performed by collision induced dissociation tandem MS disclosed the presence in motor cortex of a fucose-ganglioside Fuc-GM1 (d18 : 1/20 : 0) isomer exhibiting both N-acetylneuraminic acid and fucose residues linked to the inner galactose.