Molecular glycopathology by capillary electrophoresis: Analysis of the N‐glycome of formalin‐fixed paraffin‐embedded mouse tissue samples

Capillary electrophoresis with laser‐induced fluorescence (CE‐LIF) detection was used to analyze endoglycosidase released and fluorophore‐labeled N‐glycans from formalin‐fixed paraffin‐embedded (FFPE) mouse tissue samples of lung, brain, heart, spleen, liver, kidney and intestine. The FFPE samples were first deparaffinized followed by solubilization and glycoprotein retrieval. PNGase F mediated release of the N‐linked oligosaccharides was followed by labeling with aminopyrene trisulfonate. After CE‐LIF glycoprofiling of the FFPE mouse tissues, the N‐glycan pool of the lung specimen was subject to further investigation by exoglycosidase array based carbohydrate sequencing. Structural assignment of the oligosaccharides was accomplished by the help of the GUcal software and the associated database, based on the mobility shifts after treatments with the corresponding exoglycosidase reaction mixtures. Sixteen major N‐linked carbohydrate structures were sequenced from the mouse lung FFPE tissue glycome and identified, as high mannose (3) neutral biantennary (3) sialylated monoantennary (1) and sialylated bianennary (9) oligosaccharides. Two of these latter ones also possessed alpha(1‐3) linked galactose residues.