chondroitin-sulfates and Scleroderma--Systemic

Apoptosis of endothelial cells (EC) is appreciated as a primary pathogenic event in systemic sclerosis. Yet, how apoptosis of EC leads to fibrosis remains to be determined. We report that apoptosis of EC triggers the release of novel fibrogenic mediators. Medium conditioned by apoptotic EC (SSC) was found to inhibit apoptosis of fibroblasts, whereas medium conditioned by EC in which apoptosis was blocked (with either pan-caspase inhibition or Bcl-x(L) overexpression) did not. PI3K was activated in fibroblasts exposed to SSC. This was associated with downstream repression of Bim-EL and long-term up-regulation of Bcl-x(L) protein levels. RNA interference for Bim-EL in fibroblasts blocked apoptosis. SSC also induced PI3K-dependent myofibroblast differentiation with expression of alpha-smooth muscle actin, formation of stress fibers, and production of collagen I. A C-terminal fragment of the domain V of perlecan was identified as one of the fibrogenic mediators present in SSC. A synthetic peptide containing an EGF motif present on the perlecan fragment and chondroitin 4-sulfate, a glycosaminoglycan anchored on the domain V of perlecan, induced PI3K-dependent resistance to apoptosis in fibroblasts and myofibroblast differentiation. Human fibroblasts derived from sclerodermic skin lesions were more sensitive to the antiapoptotic activities of the synthetic peptide and chondroitin 4-sulfate than fibroblasts derived from normal controls. Hence, we propose that a chronic increase in endothelial apoptosis and/or increased sensitivity of fibroblasts to mediators produced by apoptotic EC could form the basis of a fibrotic response characterized by sustained induction of an antiapoptotic phenotype in fibroblasts and persistent myofibroblast differentiation.

Topics: Adult; Amino Acid Sequence; Apoptosis; Cell Differentiation; Cell Line; Chondroitin Sulfates; Culture Media, Conditioned; Endothelium, Vascular; Fibroblasts; Heparan Sulfate Proteoglycans; Humans; Immunity, Innate; Inflammation Mediators; Molecular Sequence Data; Peptide Fragments; Phosphatidylinositol 3-Kinases; Protein Structure, Tertiary; Scleroderma, Systemic; Signal Transduction

UDP-D-xylose:proteoglycan core protein beta-D-xylosyltransferase (EC2.4.2.26) is the initial enzyme in the biosynthesis of chondroitin sulfate and dermatan sulfate proteoglycans in fibroblasts and chondrocytes. Secretion of xylosyltransferase into the extracellular space was determined in cultured human dermal fibroblasts. A more than 6-fold accumulation of xylosyltransferase activity in cell culture supernatant was observed (day 1, 0.6 microU per 106 cells; day 9, 4.1 microU per 106 cells); however, intracellular xylosyltransferase activity remained at a constant level (0.4 microU per 106 cells). Exposure of human chondrocytes to colchicine led to a 3-fold decreased level of xylosyltransferase and chondroitin-6-sulfate concentration in cell culture. Specific xylosyltransferase activity and chondroitin-6-sulfate concentration decreased in a concentration-dependent manner and in parallel in culture medium and accumulated 5-fold in cell lysates indicating that xylosyltransferase is secreted simultaneously into the extracellular space with chondroitin sulfate proteoglycans. Xylosyltransferase activities were determined in serum samples of 30 patients with systemic sclerosis. Xylosyltransferase activities in female (mean value 1.28 mU per liter, 90% range 1.10-1.55 mU per liter) and male patients (mean 1.39 mU per liter, 90% range 1.16-1. 57 mU per liter) with systemic sclerosis were significantly increased in comparison with blood donors of a corresponding age. Furthermore, xylosyltransferase activity was correlated with the clinical classification of systemic sclerosis. Female patients with diffuse cutaneous systemic sclerosis showed higher serum xylosyltransferase activities than patients with limited systemic sclerosis. These results confirm that the increase of proteoglycan biosynthesis in sclerotic processes of scleroderma is closely related to an elevated xylosyltransferase activity in blood and demonstrate the validity of xylosyltransferase as an additional diagnostic marker for determination of sclerotic activity in systemic sclerosis.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers; Cartilage; Cells, Cultured; Chondroitin Sulfates; Colchicine; Extracellular Space; Female; Fibroblasts; Humans; Longitudinal Studies; Male; Middle Aged; Pentosyltransferases; Scleroderma, Systemic; Skin; UDP Xylose-Protein Xylosyltransferase

We report a case of atrophoderma of Pasini and Pierini. We determined the glycosaminoglycan content in the involved skin. Dermatan sulfate content in the involved skin (1.88 micrograms uronic acid/mg dry skin) was greater than that in the uninvolved skin (1.05 micrograms uronic acid/mg dry skin). No significant differences in hyaluronic acid, chondroitin sulfate or heparan sulfate content between involved and uninvolved skin were observed. These results suggest that abnormal metabolism of dermatan sulfate may be involved in the pathogenesis of atrophoderma; this pattern has been observed in systemic or localized scleroderma.

Topics: Adult; Atrophy; Chondroitin Sulfates; Dermatan Sulfate; Glycosaminoglycans; Heparitin Sulfate; Humans; Hyaluronic Acid; Male; Pigmentation Disorders; Scleroderma, Localized; Scleroderma, Systemic; Skin; Uronic Acids

The disaccharide contents of chondroitinase-digestible glycosaminoglycans extracted from a 6-mm punch biopsy of the forearm skin were determined using high-performance liquid chromatography after 1-phenyl-3-methyl-5-pyrasolone labelling. In 9 patients with systemic sclerosis, the amounts of both the main disaccharide unit of dermatan sulfate and chondroitin sulfate C increased significantly, as compared with 7 site-matched controls. Furthermore, the increase in dermatan sulfate was significantly correlated with both the clinical severity and the extent of skin sclerosis, while the main disaccharide unit of hyaluronic acid tended to decrease. These results confirm that changes in skin glycosaminoglycans are closely related to fibrotic processes and suggest that the alterations of disaccharide components may play a role in the collagen deposition in systemic sclerosis.

Topics: Aged; Chondroitin Sulfates; Dermatan Sulfate; Disaccharides; Female; Glycosaminoglycans; Humans; Male; Middle Aged; Scleroderma, Systemic; Skin

The disaccharides constituting chondroitinase-digestible glycosaminoglycan (GAG) in the skin lesions of patients with systemic sclerosis were determined using high-performance liquid chromatography (HPLC). In scleroderma there was an increase in the amount of delta Di-4S(DS), the main disaccharide unit of dermatan sulphate, and a decrease in delta Di-HA, the disaccharide unit of hyaluronic acid, as compared with normal skin from a similar site. The distribution pattern of the main disaccharides constituting chondroitin sulphate and dermatan sulphate in scleroderma differed from that in scars or scleredema.

Topics: Adult; Aged; Chondroitin Sulfates; Chromatography, High Pressure Liquid; Dermatan Sulfate; Disaccharides; Female; Glycosaminoglycans; Humans; Hyaluronic Acid; Male; Middle Aged; Scleroderma, Systemic; Skin

Systemic lupus erythematosus (SLE) is an autoimmune disease which involves the basement membranes of blood vessels in multiple organs. An important component of the microvasculature is vascular heparan sulfate proteoglycan (HSPG). In this study, we investigated the presence in SLE and other immune disease sera of autoantibodies to purified vascular HSPG. Our data demonstrate that antibody to HSPG is found primarily in SLE sera, and not in sera from controls or patients with other immune diseases. The titer of antibody to HSPG correlated with complement depletion in SLE sera. Antibody to HSPG was frequently found in high titer in SLE patients with renal and neurologic involvement. These studies indicate that our assay for antibody to vascular HSPG detects a pathologically relevant autoantibody in SLE sera. The implications of our findings for pathogenesis of vascular autoimmunity are discussed, including the relationship of anti-vascular HSPG antibody to anti-DNA and antiphospholipid antibodies.

Topics: Administration, Topical; Anti-Inflammatory Agents; Antibody Specificity; Arthritis, Rheumatoid; Basement Membrane; Blotting, Western; Chondroitin Sulfates; Collagen; Complement System Proteins; Dose-Response Relationship, Immunologic; Enzyme-Linked Immunosorbent Assay; Fibronectins; Heparin; Heparitin Sulfate; Humans; Hyaluronic Acid; Laminin; Lupus Erythematosus, Systemic; Muscle, Smooth, Vascular; Polymyalgia Rheumatica; Proteoglycans; Scleroderma, Systemic; Sjogren's Syndrome

The compositional changes of acidic glycosaminoglycans (AGAG) in the urine of progressive systemic sclerosis (PSS) patients were studied using chondroitinases and heparitinase in appropriate enzyme assays and by electrophoretic characterization. Daily urinary excretion of AGAG in patients with PSS was increased, when compared to normals. The proportion of urinary AGAG in PSS patients, which was undigested by chondroitinase-ABC (most probably representing heparan sulfates (HS)), increased significantly from the normal value. The substance was found to be mainly HS as determined by the electrophoretic pattern, thin-layer chromatographic analysis and by its susceptibility to heparitinase. After digestion of urinary chondroitin sulfate isomers with chondroitinases, the unsaturated disaccharides were mainly separated into 4-sulfated and 6-sulfated disaccharide units by paper chromatography. In all of the patients with PSS, the ratio of the unsaturated 4-sulfated disaccharide to the unsaturated disaccharide was higher than that in normal subjects. These observations indicate an abnormal turnover of AGAG in patients with PSS.

Topics: Adolescent; Adult; Aging; Chondroitin Sulfates; Chondroitinsulfatases; Chromatography, Gel; Chromatography, Paper; Chromatography, Thin Layer; Electrophoresis, Cellulose Acetate; Female; Glycosaminoglycans; Heparitin Sulfate; Humans; Male; Middle Aged; Polysaccharide-Lyases; Scleroderma, Systemic; Uronic Acids