heparitin-sulfate and Nephrosis

Topics: Animals; Collagen; Doxorubicin; Epithelium; Glomerulonephritis; Heparitin Sulfate; Humans; Kidney Glomerulus; Nephrosis; Puromycin Aminonucleoside

Heparan sulfate (HS) in the glomerular basement membrane (GBM) is important for regulation of the charge-dependent permeability. Heparanase has been implicated in HS degradation in several proteinuric diseases. This study analyzed the role of heparanase in HS degradation in Adriamycin nephropathy (AN), a model of chronic proteinuria-induced renal damage. Expression of heparanase, HS, and the core protein of agrin (to which HS is attached) was determined on kidney sections from rats with AN in different experiments. First, expression was examined in a model of unilateral AN in a time-course study at 6-wk intervals until week 30. Second, rats were treated with the hydroxyl radical scavenger dimethylthiourea (DMTU) during bilateral AN induction. Finally, 6 wk after AN induction, rats were treated with angiotensin II receptor type 1 antagonist (AT1A) or vehicle for 2 wk. Heparanase expression was increased in glomeruli of rats with AN, which correlated with HS reduction at all time points and in all experiments. Treatment with DMTU prevented the increased heparanase expression, the loss of GBM HS, and reduced albuminuria. Finally, treatment of established proteinuria with AT1A significantly reduced heparanase expression and restored glomerular HS. In conclusion, an association between heparanase expression and reduction of glomerular HS in AN was observed. The effects of DMTU suggest a role for reactive oxygen species in upregulation of heparanase. Antiproteinuric treatment by AT1A decreased heparanase expression and restored HS expression. These results suggest involvement of radicals and angiotensin II in the modulation of GBM permeability through HS and heparanase expression.

Topics: Agrin; Angiotensin Receptor Antagonists; Animals; Doxorubicin; Enzyme Induction; Gene Expression Regulation; Glomerular Basement Membrane; Glucuronidase; Heparitin Sulfate; Imidazoles; Kidney Tubules; Male; Nephrosis; Proteinuria; Rats; Rats, Wistar; Reactive Oxygen Species; Renin-Angiotensin System; Tetrazoles; Thiourea

Mesangial cell proliferation is found in many forms of progressive renal disease. This proliferation may be due to dysregulation of mesangial cell growth. The studies presented here test the hypothesis that the normal glomerulus produces a regulator of mesangial cell growth. Conditioned media (CM) from primary glomerular cultures were able to inhibit rat mesangial cell growth in a dose- and time-dependent fashion, from 30.0 +/- 3.8 to 86.6 +/- 3.9% growth inhibition. The growth inhibitor in glomerular CM appears to have a molecular weight of less than 3,000. Glomerular CM caused significantly more growth inhibition than did 3T3 fibroblast CM, 77.9 +/- 2.8% growth inhibition by 10% glomerular CM versus 21.2 +/- 5.4% by 10% 3T3 CM (P < 0.001). The growth inhibition was completely reversible. Glomerular CM had no effect on the growth of 3T3 fibroblasts. Treatment of the glomerular CM with either trypsin or neutral protease had no effect on its growth inhibitory activity. Glomerular CM obtained from rats with puromycin aminonucleoside nephrosis caused significantly less growth inhibition than did control glomerular CM; at a concentration of 10% CM, control glomerular CM had 65.1 +/- 1.9% growth inhibition and puromycin had 45.4 +/- 2.1% (P < 0.001). Thus, the rat glomerulus produces a small, nonprotein inhibitor of rat mesangial cell growth and the activity of this inhibitor is reduced in puromycin nephrosis. Impairment of mesangial cell growth regulation may be important in the pathogenesis of progressive renal disease.

Topics: 3T3 Cells; Animals; Cell Division; Cells, Cultured; Culture Media, Conditioned; Female; Glomerular Mesangium; Growth Inhibitors; Heparitin Sulfate; Kidney Glomerulus; Mice; Molecular Weight; Nephrosis; Organ Specificity; Puromycin; Rats; Rats, Sprague-Dawley

Renal glomerular basement membranes (GBMs) exhibit a charge-selective barrier, consisting of heparan sulfate proteoglycan (HSPG) that restricts the passage of anionic molecules into the urine. Previous efforts to localize the HSPG core protein within various layers of the GBM have been contradictory. Furthermore, attempts to correlate proteinuria in several disease states with a decrease in anionic sites of HSPG core protein have yielded conflicting results. When antibodies to HSPG from the EHS tumor matrix [anti-(EHS) HSPG] and GBMs [anti-(GBM) HSPG] were used together with immunogold to label renal tissues from puromycin aminonucleoside nephrotic (PAN) rats, immunolabeling results indicated that a portion of the protein core recognized by anti-(EHS) HSPG was significantly reduced, while immunolabeling with anti-(GBM) HSPG was only slightly reduced in early PAN. Anionic sites (stained with the cationic probe, polyethyleneimine) within the lamina rara externa of the GBM remained unaltered throughout the course of PAN.

Topics: Animals; Basement Membrane; Disease Models, Animal; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Immunohistochemistry; Kidney Glomerulus; Male; Nephrosis; Proteoglycans; Puromycin Aminonucleoside; Rats; Rats, Inbred Strains

The present studies were designed to analyze mRNA levels of basement membrane components including collagen IV, laminin, and heparan sulfate proteoglycan (HSPG) in the course of puromycin aminonucleoside (PAN) nephrosis. mRNA levels for alpha 1 (IV) chain; laminin A, B1, and B2 chains; and HSPG were measured in glomeruli of PAN nephrotic rats 0, 2, 8, 14, and 20 days after PAN injection. In the nephrotic stage of PAN nephrosis (on the 8th day), mRNA levels for alpha 1 (IV) chain and laminin A, B1, and B2 chains increased, whereas those for HSPG decreased. The anionic sites in glomerular basement membrane stained by polyethyleneimine were smaller in size and fewer in number in PAN nephrotic rats than they were in control rats. In the remission stage of PAN nephrosis (on the 20th day), however, mRNA levels for alpha 1 (IV) chain and laminin A, B1, and B2 chains decreased, whereas mRNA levels for HSPG increased. Polyethyleneimine aggregates in this stage appeared to be larger and more intense than those in the nephrotic stage. These results indicate that the expression of basement membrane genes for alpha 1 (IV), laminin, and HSPG was abnormally regulated in PAN nephrosis and that this abnormal gene regulation might contribute to the development of proteinuria.

Topics: Animals; Basement Membrane; Blotting, Northern; Collagen; DNA Probes; Fluorescent Antibody Technique; Gene Expression Regulation; Heparitin Sulfate; Kidney Glomerulus; Laminin; Male; Microscopy, Electron; Nephrosis; Polyethyleneimine; Proteinuria; Puromycin Aminonucleoside; Rats; Rats, Inbred Strains; RNA, Messenger

Status of glomerular proteoglycans (PGs) in puromycin aminonucleoside nephrosis was investigated. Rats were made nephrotic and sacrificed 0, 7, 14, and 21 days later. Maximal proteinuric response was observed between 7 and 14 days. Prior to sacrifice, they received injections of conjugated or unconjugated anti-heparan-sulfate-proteoglycan antibody, directed against its core protein (Mr = 18,000). Their kidneys were processed for direct and indirect immunofluorescence, immunoperoxidase, tannic-acid staining, and tissue autoradiography (ARG). By tannic-acid staining, antibody binding sites identical to the anionic sites described previously were discovered. No qualitative differences were observed by these immunohistochemical techniques. Quantitative tissue ARG did not reveal any statistical differences in the binding of antibody between the control and nephrotic groups. For de novo biosynthetic studies, rats were sacrificed on day 10. Their kidneys were utilized for labeling of basement membrane PGs by employing [35S]-sulfate as the precursor product. Tissue ARG, as well as biochemical studies, were performed on the radiolabeled glomeruli. PGs were extracted with 4 M GuCl and characterized by Sepharose CL-6B and DEAE-Sephacel chromatography. There was an overall increase in the total incorporated radioactivities in the glomerular and media fractions. No differences were observed in the macromolecular size characteristics of intact PGs and glycosaminoglycan chains of either glomerular or media fractions. However, an increase in the charge-density characteristics was observed in PGs of the nephrotic group. By tissue ARG, an increase in the grain densities over the basement membrane and mesangial matrices of the glomerulus was noted. These data indicate that the intact PGs, their chains and core protein do not undergo significant biochemical alterations; however, de novo synthesized PGs have higher charge-density characteristics which may be related to a higher degree of sulfation that occurs during the course of aminonucleoside nephrosis.

Topics: Animals; Autoradiography; Chondroitin Sulfate Proteoglycans; Female; Glycosaminoglycans; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Histocytochemistry; Hydrolyzable Tannins; Immunologic Techniques; In Vitro Techniques; Kidney Glomerulus; Microscopy, Electron; Nephrosis; Proteinuria; Proteoglycans; Puromycin; Puromycin Aminonucleoside; Rats; Rats, Inbred F344; Staining and Labeling

Changes in glomerular anionic sites in puromycin aminonucleoside nephrosis (PAN) in the rat are controversial. The authors examined glomerular anionic sites in PAN by in vivo staining with polyethyleneimine (PEI). They also quantitated and characterized glomerular heparan sulfate (HS), which is known to be a major glomerular polyanion in PAN, using in vivo incorporation of 35S-sulfate. PAN rats had a mean protein excretion of 96 +/- 23 mg per 24 hours. Staining of anionic sites with PEI showed 15.3 +/- 2.8 sites per 1000-nm length of glomerular basement membrane in controls, 13.7 +/- 1.9 sites in PAN rats (P greater than 0.05), and 50% of rats with early PAN had absent staining. Total 35S-sulfate incorporation was similar in both the controls and established PAN rats (2900 +/- 150 dpm/mg dry wt of glomeruli versus 3005 +/- 260, P greater than 0.05) but decreased in early PAN rats (2025 +/- 148). The percentage of 35S-sulfate incorporated into chondroitin sulfate was similar in all three groups of animals. HS uronic acid was also similar (1.8 +/- 0.2 g/mg dry wt of glomeruli versus 1.7 +/- 0.3, P greater than 0.05) but decreased in early PAN (1.1 +/- 0.2). The distribution of 35S-sulfate activity within the HS subfractions was examined by ion-exchange chromatography and showed a shift in percent present from 1.0 M to 1.25 M fraction in established and early PAN animals (control 1.0 M 37% +/- 3.2% versus PAN 19% +/- 3.4%, P less than 0.01, and 1.25 M 36% +/- 2.9% versus 53% +/- 2.9%, P less than 0.01). These results demonstrate that glomerular heparan sulfate is unchanged in established PAN but decreased in early PAN. SO4 incorporation is unchanged in established PAN and diminished in early PAN. Thus, early in PAN HS synthesis is impaired, but in established PAN the HS is normal, and changes in glomerular HS cannot explain the increased permeability.

Topics: Animals; Anions; Chondroitin Sulfates; Female; Glycosaminoglycans; Heparitin Sulfate; Kidney Glomerulus; Microscopy, Electron; Nephrosis; Polyethyleneimine; Puromycin; Puromycin Aminonucleoside; Rats; Rats, Inbred Strains; Staining and Labeling; Sulfates; Uronic Acids

The distribution of heparan sulfate proteoglycan (HS-PG) was examined electron microscopically by the high iron diamine (HID) method in puromycin aminonucleoside (PAN) nephrosis, accelerated Masugi nephritis (NTN), and serum sickness nephritis induced by bovine serum albumin (BSA nephritis) in the rat. In PAN nephrosis rats, no change was observed in the distribution of HS-PG in the lamina rara externa (LRE) of the glomerular basement membrane (GBM) throughout the experiment. In NTN rats, however, the loss of HS-PG was observed, and it was associated with subepithelial electron dense deposits formed possibly by serum sickness mechanism, but not with inflammatory cell infiltration. In BAS nephritis, immune deposits were seen in mesangial, subendothelial, intramembranous and subepithelial areas. The deposits in the former three areas seemed to have little reciprocity with the loss of HS-PG and proteinuria. Urinary protein increased in accordance with the development of subepithelial deposits and the loss of HS-PG in the area of the deposits in the LRE. These results indicate that HS-PG could be preserved even in marked proteinuric states in morphologically intact basement membrane, but altered and lost distribution of HS-PG associated with subepithelial immune deposits could in turn result in the development of proteinuria.

Topics: Animals; Chondroitin Sulfate Proteoglycans; Glycosaminoglycans; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Kidney Cortex; Kidney Glomerulus; Male; Microscopy, Electron; Nephritis; Nephrosis; Proteinuria; Proteoglycans; Rats; Rats, Inbred Strains; Serum Albumin, Bovine

Alterations in the permeability of the glomerular basement membrane (GBM) towards native ferritin (NF) and iodinated albumin (125I-BSA) following removal of the major glycosaminoglycans (GAGs) of the GBM, heparan sulfate (HS) and hyaluronic acid (HA), were assessed utilizing the techniques of routine electron microscopy and autoradiography, respectively. Kidneys were incubated with heparinase (to degrade the GAGs of the GBM) and subsequently perfused with either NF or 125I-BSA. Control kidneys, which were not treated with heparinase, showed a low permeability to both tracers, with NF being confined to the lamina rara interna and 125I-BSA exhibiting a low level of passage into the urinary spaces (as indicated by a low density of autoradiographic grains over the urinary spaces). After heparinase treatment there was an increase in the permeability of the GBM such that both NF and 125I-BSA passed through the GBM in larger quantities and entered the urinary spaces. Perfusion of cationized ferritin (CF) into control kidneys revealed this probe to bind to the HS-rich anionic sites present within the GBM. Treatment with heparinase resulted in an abolition of the CF binding thereby indicating that the sites are composed mainly of HS and that HS plays a key role in establishing the permeability properties of the GBM. The changes in the pattern of distribution and density of the anionic sites of the GBM following induction of nephrosis was also studied. Animals were rendered nephrotic by subcutaneous injections of an aminonucleoside of puromycin and their kidneys subsequently perfused with either CF or cationized cytochrome c. No difference in either the pattern of distribution on density of the anionic sites in the GBM of nephrotic kidneys was observed when compared to nonnephrotic controls; thus indicating that the proteinuria associated with aminonucleoside nephrosis might be due to changes in components of the glomerular capillary wall other than the anionic sites.

Topics: Animals; Basement Membrane; Binding Sites; Capillary Permeability; Cell Membrane Permeability; Ferritins; Glycosaminoglycans; Heparitin Sulfate; Kidney Glomerulus; Male; Nephrosis; Rats; Serum Albumin