engleski

Mass Spectrometry-Based Characterization of Composition and Structure of Gangliosides as Human Brain Biomarkers in Health and Disease

Comparing to mammalian non-neural cell types, brain cells contain the highest concentrations and the most complex compositions of sialylated glycosphingolipids – gangliosides. Gangliosides are primarily plasma-membrane components, enriched in membrane microdomains, and expressed, by their carbohydrate moieties, as cell surface antigens. They participate in vital cellular processes: cell-to-cell communication, cell signaling, growth, differentiation, apoptosis etc. Their composition is species- and cell type-specific. In human brain, distribution of gangliosides is neuroanatomical region-specific ; the patterns specifically change during brain development, maturation and aging, while characteristic aberrations of the normal patterns occur due to diseases (e.g. malignant alteration, neurodegeneration). Gangliosides are, therefore, recognized as valuable neurodevelopmental markers and screened as potential diagnostic markers of diseases or therapeutic targets. Also, their usage as therapeutic agents has been under clinical trials. Our groups continuously participate in characterizing biomarker ganglioside compositions and individual structures of defined human brain regions during development and aging, as well as of the histopatologically defined brain tumors. To collect detailed systematic and comparative data about ganglioside compositions including identification of novel structures we have implemented and optimized sensitive mass spectrometric (MS) approaches allowing ganglioside screening and sequencing directly from native complex mixtures of total gangliosides extracted and purified from tissue samples. The following MS systems have been used: capillary- or fully automated chip-based nanoelectrospray ionization interfaced to high-performance tandem mass spectrometers - a high-capacity ion trap MS, quadrupole time-of-flight MS, and Fourier-transform ion cyclotron resonance MS. Employing these MS approaches in complementation with chromatographic and immunochemical methods, we have documented that specific ganglioside patterns contain much larger number of individual species than previously reported. In this contribution, analytical potential of the mentioned strategies will be shown. Results will be presented demonstrating complexity of data collected by applying these strategies to characterize total ganglioside mixtures from selected regions of fetal/adult brain and brain tumors (glioblastoma, astrocytoma, meningioma, haemangioma, adenocarcinoma brain metastasis).

gangliosides; human brain; diagnostic markers; mass spectrometry

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