chondroitin and Progeria

A small proteoglycan that contains only a single dermatan sulfate chain is the main proteoglycan synthesized by skin fibroblasts. Fibroblasts from a patient with progeroidal appearance and symptoms of the Ehlers-Danlos syndrome have a reduced ability of converting the core protein of this proteoglycan into a mature glycosaminoglycan chain-bearing species. This abnormality is the consequence of a deficiency in galactosyltransferase I (xylosylprotein 4-beta-galactosyltransferase; EC 2.4.1.133), which catalyzes the second glycosyl transfer reaction in the assembly of the dermatan sulfate chain. The glycosaminoglycan-free core protein secreted by the patient's fibroblasts bears an unsubstituted xylose residue. The mutant enzyme is abnormally thermolabile. Preincubation of fibroblasts at 41 degrees C leads to a further reduction in the production of mature proteoglycan and affects the capacity for glycosaminoglycan synthesis on p-nitrophenyl beta-D-xyloside more strongly in the mutant than in control cells.

Topics: Carbohydrate Sequence; Cells, Cultured; Chondroitin; Chondroitin Sulfate Proteoglycans; Dermatan Sulfate; Female; Fibroblasts; Galactosyltransferases; Humans; Kinetics; Male; Molecular Sequence Data; Progeria; Proteoglycans; Reference Values; Skin; Temperature; Xylose

WI-38 fibroblasts from 'normal' individuals and skin fibroblasts from patients displaying classical symptoms of progeria (accelerated aging) were maintained in tissue culture with and without periodic supplementation of 0.25 mg/ml of chondroitin-4-sulphate (C-4-S) during the ultimate phase of slowed division (phase 3). When C-4-S was not present in the culture medium, cell counts (not necessarily indicative of relative rates of cell division) and mean cell volumes were lower, and intracellular aberrations were higher, in both types of fibroblasts (normal and progeria) at, and even before, the 47th-50th and 13th-16th passages, respectively. The authors emphasise effects of C-4-S in preserving normal ultrastructure, pointing out that C-4-S does not fulfil the criteria of a mitogen and that any possible increases in rates of mitosis following supplementation with this substance are probably secondary to an enhanced metabolic environment.

Topics: Cell Survival; Cells, Cultured; Chondroitin; Chondroitin Sulfates; Fibroblasts; Humans; Progeria

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.

Topics: Chondroitin; Chondroitin Lyases; Chondroitin Sulfates; Chromatography, High Pressure Liquid; Glycosaminoglycans; Humans; Hyaluronic Acid; Oculocerebrorenal Syndrome; Progeria; Werner Syndrome