Glycoprotein metabolism in neuronal ceroid lipofuscinosis fibroblasts.

Human skin fibroblast lines of the infantile form of neuronal ceroid lipofuscinosis and control lines were cultured in the presence of [3H]glucosamine plus [3H]mannose and [35S]methionine. The labeled glycoconjugates were compared by quantitative polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The infantile form of the disease showed a 75% decrease of four glycoprotein components of M(r) 120-140 kDa. These components appeared to be N-linked glycoproteins as peptide-N4-(N-acetyl-beta-glucosaminyl) asparagine amidase (PNGase F) released 86-96% of the labeled carbohydrate from the labeled protein. These results suggest that the infantile form of this disease may be characterized by abnormalities in glycoconjugate metabolism leading to reduction of specific glycoproteins.

Characterization of proteoglycans in Alzheimer's disease fibroblasts.

Skin fibroblasts lines established from patients with Alzheimer's disease and old normal individuals were cultured with 35S-sodium sulfate and 3H-glucosamine. Proteoglycans were isolated and characterized. Sulfate incorporation into proteoglycans increased in Alzheimer's disease fibroblasts relative to normal controls. These increases changed the ratio of chondroitin sulfate to heparan sulfate proteoglycan from 1.4 to 1.7 (p = 0.0012) and decreased the ratio of cell to medium proteoglycans from 0.32 to 0.26 in normal and Alzheimer fibroblasts (p = 0.006), respectively. HPLC analysis of the disaccharides produced by chondroitinase ABC revealed no differences in composition between proteoglycans of Alzheimer and normal fibroblasts in either the cell or medium fraction. However, analysis of disaccharides produced by heparinase plus heparitinase showed differences in composition in the medium but not the cell fraction. delta UA-GlcNS was increased by 30% while delta UA-GlcNS-6S was reduced by 40% in Alzheimer's disease.

High pressure liquid chromatographic identification of hyaluronic acid and chondroitin sulphate disaccharides.

In this report we describe a system capable of resolving all of the known unsaturated disaccharides derived from the chondroitin sulphates, dermatan sulphate and hyaluronic acid by chondroitinase digestion. This system is superior to others in that the non-sulphated and mono-, di- and tri-sulphated disaccharides can be separated with good resolution in approximately 40 min in an isocratic solvent. The system employs an amino-cyano silica gel column (Whatman Partisil 5 PAC, 25 cm) and is eluted with an isocratic solvent consisting of 48% (v/v) acetonitrile, 14% (v/v) methanol and 38% (v/v) aqueous buffer. This aqueous buffer contains 0.5 M Tris-HCl, 0.1 M boric acid, 23.4 mM sulphuric acid, pH 8.0. UV absorption is monitored at 229 nm and for most disaccharides as little as 150 ng can be reliably determined. The addition of boric acid to the eluent is essential for good resolution of all components and the addition of low concentrations of sulphuric acid is used to control the elution times of various components. The system was applied to the analysis of glycosaminoglycan standards and excellent agreement with previous compositional analyses was obtained.

Elevation of urinary hyaluronic acid in Werner's syndrome and progeria.

Werner's syndrome and Hutchinson-Gilford progeria syndrome (progeria) are human genetic diseases which may serve as models for the study of premature aging. The basic defects underlying these diseases are unknown. An abnormally high level of urinary hyaluronic acid (HA) excretion has been previously reported in several Werner's and one progeria subject, all from Japan. To determine if a high HA level is a reliable marker for these diseases, we quantitated the urinary excretion of HA in three progeria subjects, one subject with an atypical progeroid syndrome, and a Werner's syndrome subject. Compared to controls, the total urinary HA was found to be markedly increased in the three progeria samples and in the Werner's syndrome sample. These findings support the previous observations indicating elevated HA may be a specific marker for these diseases.

Analysis by high-performance liquid chromatography of hyaluronic acid and chondroitin sulfates.

The use of high-performance liquid chromatography for the quantification of glycosaminoglycan disaccharides has been hampered by the inability to isocratically resolve the chondroitinase digestion products 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-D-glucose (delta Di-HA) and 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-D-galactose (delta Di-OS). To overcome this limitation, we have developed a solvent system capable of resolving delta Di-HA, delta Di-OS, 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose (delta Di-6S), and 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose (delta Di-4S). Integrator responses were linear from 1 microgram down to 25 ng for delta Di-HA, delta Di-OS, and delta Di-4S and down to 100 ng for delta Di-6S. This method was used to examine changes in the content of urinary hyaluronic acid and chondroitin sulfates isolated from normal individuals and from patients with Lowe Syndrome, Werner Syndrome, and Hutchinson-Gilford Progeria Syndrome. We confirmed that the HPLC method gave results comparable to colorimetric methods.

Urinary hyaluronic acid elevation in Hutchinson-Gilford progeria syndrome.

The basic genetic defect in the Hutchinson-Gilford Progeria Syndrome (progeria), a premature aging syndrome, is unknown. To investigate possible defects in hyaluronic acid (HA) metabolism in this disease, the urinary excretion of HA was studied. Urine specimens from 11 patients with this disorder were examined for HA by a novel high performance liquid chromatography (HPLC) technique. In patients with progeria, HA excretion ranged from 169 micrograms HA/g creatinine to 1440 micrograms HA/g creatinine. In normal age-matched controls, HA excreted ranged from 0 to 77 micrograms HA/g creatinine. In all, a mean 17-fold increase in HA excretion was observed in patients with progeria when compared with age-matched normal controls. Total glycosaminoglycan (GAG) excretion was not elevated. Amongst normal controls, a modest age-related increase in HA excretion was observed. These results suggest that urinary HA levels are abnormally elevated in progeria.

Ultrastructural, neurological, and glycosaminoglycan abnormalities in lowe's syndrome.

The oculocerebrorenal syndrome (OCRS), Lowe's syndrome, is an X-linked, recessive disease characterized by mental retardation, congenital corneal abnormalities and cataracts, growth failure, rickets, osseous abnormalities, renal dysfunction with periodic acidosis, hypotonia, and areflexia. Ultrastructural studies of skin biopsy specimens in three individuals with the disorder (aged 17, 9, and 8 years) revealed cytoplasmic, membrane-bound, electron-lucent vacuoles and some electron-dense membranous inclusion bodies in fibroblasts and Schwann cells, as well as axonal degeneration and vascular changes. Computed tomographic scans evidenced brain atrophy. Urinary excretion of glycosaminoglycans (GAG) was four to five times greater than in normal controls. The predominant urinary GAG was a low-sulfated chondroitin-4-sulfate; chondroitin-6-sulfate and heparan sulfate excretion levels were normal. A tenfold increase in urinary GAG excretion was found in one patient with oculocerebrorenal syndrome during periods of behavioral agitation. These findings suggest that the clinical stigmata of oculocerebrorenal syndrome may be related to a defect in GAG metabolism.

Low sulfated glycosaminoglycans are excreted in patients with the Lowe syndrome.

Glycosaminoglycans (GAGs) were prepared from the urine of three patients and from normal individuals by cetylpyridinium chloride precipitation and Pronase digestion. The GAGs were analyzed by electrophoresis, anion-exchange chromatography, and enzymatic and chemical degradation. Each of the three patients showed a four- to fivefold increase in urinary GAG excretion compared to normal controls and in one patient a tenfold increase was measured during a period of behavioral agitation which included joint swelling. Urinary GAGs from affected individuals were characterized by a high proportion of low sulfated molecules. The predominant low sulfated component was chondroitin-4-sulfate (C4S); however, small amounts of chondroitin-6-sulfate (C6S) were also present. Heparan sulfate (HS) was present in normal proportion (5-10%) and most of it was not low sulfated. Abnormal excretion of chondroitin (Ch), hyaluronic acid (HA), and dermatan sulfate (DS) was not detected. These findings suggest that the clinical manifestations of Lowe syndrome may be caused by a defect in GAG metabolism.

Glycosaminoglycans synthesized by tumorigenic and nontumorigenic mouse melanoma cells in culture.

Glycosaminoglycans (GG) synthesized by two tumorigenic cell lines and a nontumorigenic, immunoprotective cell line derived from the B16 mouse melanoma were metabolically labeled with Na235SO4 and [3H]glucosamine. The radioactive GG synthesized at low and high cell densities were prepared from cells and culture media and analyzed by enzymatic and chromatographic methods. The cell-associated and medium GG from both low- and high-density cultures of the nontumorigenic, immunoprotective line contained a significantly higher proportion of heparin and heparan sulfate (85-95% of total) relative to comparable fractions from the tumorigenic lines. In addition to synthesizing less heparin and heparan sulfate and more chondroitin 4-sulfate plus chondroitin 6-sulfate, the tumorigenic lines differed in that the amelanotic line produced significant amounts of dermatan sulfate which remained cell associated. None of the lines produced measurable amounts of hyaluronic acid. In addition, the nontumorigenic immunoprotective line incorporated two to six times more precursor into total GG and released a higher proportion into the growth medium than did the tumorigenic lines.

A simple and rapid method for isolation of reduced carbohydrate fragments from the linkage region of cartilage keratan sulphate.

The method described is a simple and rapid procedure for isolation in high yield of carbohydrate fragments containing terminal galactosaminitol derived from the polysaccharide-protein linkage region of cartilage keratan sulphate. It is based on the observation that reducing sugars bind tightly to Dowex-1 resin (hydroxide form), whereas reduced analogues (sugar alcohols) do not [H. Yamaguchi, S. Inamura & K. Makino (1976) J. Biochem. (Tokyo) 79, 299-303].

2-O-methyl-D-glucuronic acid, a new hexuronic acid of biological origin.

Acid hydrolysis of the extracellular polysaccharide of Porphyridium cruentum (a unicellular red alga) produced a mixture of aldobiuronic acids and free hexuronic acids. Fractionation of this mixture on an ion-exchange column yielded a hexuronic acid characterized as the title compound. Its identity was confirmed by chromatographic comparisons with the authentic compound, by reduction to the corresponding methylated aldose, by resistance to controlled lead tetra-acetate oxidation and by chemical-ionization mass spectrometry. Complete spectra have been deposited as Supplementary Publication SUP50062 (7 pages) with the British Library (Lending Division), Boston Spa, Wetherby, W. Yorkshire LS23 7BQ, U.K., from whom copies may be obtained under the terms given in Biochem. J. (1976) 153, 5.