Brain chondroitin/dermatan sulfate, from cerebral tissue to fine structure: extraction, preparation, and fully automated chip-electrospray mass spectrometric analysis.

Chondroitin sulfate (CS) and dermatan sulfate (DS) glycosaminoglycans (GAGs) are covalently linked to proteins, building up a wide range of proteoglycans, with a prevalent expression in the extracellular matrix (ECM). In mammalian tissues, these GAG species are often found as hybrid CS/DS chains. Their structural diversity during chain elongation is produced by variability of sulfation in the repeating disaccharide units. In central nervous system, a large proportion of the ECM is composed of proteoglycans; therefore, CS/DS play a significant role in the functional diversity of neurons, brain development, and some brain diseases. A requirement for collecting consistent data on brain proteoglycan glycosylation is the development of adequate protocols for CS/DS extraction and detailed compositional and structure analysis. This chapter will present a strategy, which combines biochemical tools for brain CS/DS extraction, purification, and fractionation, with a modern analytical platform based on chip-nanoelectrospray multistage mass spectrometry (MS) able to provide information on the essential structural elements such as epimerization, chain length, sulfate content, and sulfation sites.