Structure of sialyl-oligosaccharides isolated from bronchial mucus glycoproteins of patients (blood group O) suffering from cystic fibrosis

Abstract

The carbohydrate chains of the bronchial-mucus glycoproteins of six cystic fibrosis patients with blood group 0 were released by alkaline borohydride treatment. Low-molecular-mass, monosialyl oligosaccharide-alditols were isolated by anion-exchange chromatography and fractionated by high-performance liquid chromatography. Structural characterization was performed by 500-MHz 'H-NMR spectroscopy in combination with quantitative sugar analysis. The established structures range in size from tetra-up to heptasaccharides. They are all sialyl analogs of neutral oligosaccharides that were characterized previously [Lamblin G., Boersma A., Lhermitte M., Roussel P., Mutsaers J. Human bronchial mucus is secreted as a gelatinous layer on the surface of the tracheobronchial airway epithelium and is continuously moved towards the pharynx where it is swallowed. It acts as a medium for protection and lubrication of the mucosa and for transport of inhaled particles such as dust, pollen, viruses and bacteria to clear the bronchial epithelium.Bronchial mucins, as most mucins [l], contain about 70% carbohydrate which is 0-glyosidically linked to the peptide backbone as neutral and acidic oligosaccharide chains. The acid functions stem from the presence of sialic and/or sulfate residues [2].Any change in the structure of these oligosaccharides may modify the rheological properties of the bronchial mucus and lead to a non-efficient mucociliary clearance and to destruction phenomena found in cystic fibrosis or other bronchial diseases where hypersecretion of mucus is a pre-eminent feature of the pathological process. Increased adherence of inhaled particles may be a concomitant phenomenon.Since it is difficult to obtain the amount of normal human bronchial secretion required for detailed carbohydrate structural analysis [3], we have taken mucins secreted by patients suffering from cystic fibrosis (CF) for our structural studies. In the future, the results of the structural characterization of their carbohydrates will be compared to mucins secreted by patients with other chronic bronchial hypersecretion diseases.Previously, we have isolated and characterized several lowmolecular-weight oligosaccharides that were obtained from the carbohydrate material released from the mucins occurring in the sputum of six C F patients with blood group 0 [4-61. The structures of 20 neutral and 5 sialyl-oligosaccharides were determined by 500-MHz 'H-NMR spectroscopy in conjunction with sugar composition analysis. The present paper deals with the determination of the structure of another 13 sialyloligosaccharides isolated from the same pool of CF bronchial mucins. MATERIALS AND METHODS Isolation and purijkation of human bronchial sialyl-oligosaccharidesMucin glycoproteins were isolated from the sputum of six patients (blood group 0) suffering from cystic fibrosis as described [2]. Briefly, gelatinous bronchial mucus from the sputum was solubilized by the action of 2-mercaptoethanol (1 %, by vol.) and fractionated on an Ecteola-cellulose column with stepwi...

Isolation and structural characterization of low‐molecular‐mass monosialyl oligosaccharides derived from respiratory‐mucus glycoproteins of a patient suffering from bronchiectasis

“…because its NMR characteristics (Table 6) match those reported before for this structure (compound B-4/C-5 in the cystic fibrosis pool 1Ic of oligosaccharide-alditols [22] Fig. 4 B).…”

“…The structuralreporter-group signals of the major (70%) component of 6a (denoted hal) are clearly recognizable from the 'H-NMR spectrum. Their chemical shifts are identical to those observed for the monosialyl oligosaccharide-alditol (compound B-2/ C-4 in [22]) obtained from cystic fibrosis mucins:…”

“…Fraction 2 contains a trisaccharide consisting of GalNAc-ol, Gal and NeuAc (see Table 2). The 'H-NMR characteristics of this compound (Table 3) prove it to be the Table 3, compare [22,231). The structure of compound 8al is thus:…”

“…The chemical shift of the NeuAc H-3ax atom (6 1.697; see Table 5) is in the range usually observed for NeuAc residues involved in an (r(2+6)-linkage (compare Table 4 Table 5 differ subtly but significantly from the corresponding values for compounds listed in Table 4 that share the NeuAca(2+6NGalB(1+3~1GalNAc-ol core element: 6 1.690 and 6 2.726, respectively. The fact that the set of NeuAc H-3ax and H-3eq chemical shifts appears not to be affected by extension of the trisaccharide NeuAca(:!-t6)[GlcNAc[~(I +3)]CalNAc-ol at one or more positions of GlcNAc3 has already been successfully applied in the structural determination of some of the monosialyl oligosaccharide-alditols from the cystic fibrosis bronchial mucin pool 1Ic [22].…”

Structure of three Kdn‐containing oligosaccharide‐alditols released from oviducal secretions of Ambystoma tigrinum: characterization of the carbohydrate sequence Fuc (α1–5) [Fuc (α1–4)] Kdn (α2—3/6)

“…The Fuc (~1-2) Gal (ill-4) GlcNAc sequence is indicated by GIcNAc 6 H-1 at 6 = 4.535 ppm, Gal 4 H-1 at ~ = 4.535 and Fuc 2 H-1 at 6 = 5.308 ppm [9]. The attachment of a sialic acid residue (actually Kdn) at C-3 of Gal 3 induces an upfield shift for Gal 3 H-3, observed at 6 = 4.091 ppm.…”