heparitin-sulfate and Glomerulonephritis--Membranous

The glomerular basement membrane (GBM) is an essential component of the glomerular filtration barrier. Heparan sulfate proteoglycans such as agrin are major components of the GBM, along with α345(IV) collagen, laminin-521 and nidogen. A loss of GBM heparan sulfate chains is associated with proteinuria in several glomerular diseases and may contribute to the underlying pathology. As the major determinants of the anionic charge of the GBM, heparan sulfate chains have been thought to impart charge selectivity to the glomerular filtration, a view challenged by the negligible albuminuria in mice that lack heparan sulfate in the GBM. Recent studies provide increasing evidence that heparan sulfate chains modulate local complement activation by recruiting complement regulatory protein factor H, the major inhibitor of the alternative pathway in plasma. Factor H selectively inactivates C3b bound to surfaces bearing host-specific polyanions such as heparan sulfate, thus limiting complement activation on self surfaces such as the GBM, which are not protected by cell-bound complement regulators. We discuss mechanisms whereby the acquired loss of GBM heparan sulfate can impair the local regulation of the alternative pathway, exacerbating complement activation and glomerular injury in immune-mediated kidney diseases such as membranous nephropathy and lupus nephritis.

Topics: Agrin; Animals; Collagen Type IV; Complement Activation; Complement C3b; Complement Factor H; Gene Expression Regulation; Glomerular Basement Membrane; Glomerulonephritis, Membranous; Heparitin Sulfate; Humans; Laminin; Lupus Nephritis; Membrane Glycoproteins; Signal Transduction; Static Electricity

Background The purpose of this study was to evaluate the features of heparan sulfate proteoglycans (HSPGs) as agrins of the glomerular basement membrane (GBM) and circulating anti-heparan sulfate (HS) antibodies in lupus nephritis, comparing titers among the following groups: lupus nephritis (LN), non-renal lupus, non-lupus nephritis, and healthy controls. Methods The stage of nephritis was determined based on the kidney biopsy. Alcian blue staining and immunohistochemical (IHC) staining for agrin were performed for histological evaluation of GBM HSPGs in normal glomeruli, non-lupus membranous glomerulonephritis (MGN), and lupus MGN. The results were used for measurement of the serum anti-HS antibody titers using an enzyme-linked immunosorbent assay (ELISA) in the following groups: 38 healthy controls, 38 non-lupus nephritis, 37 non-renal lupus, and 38 LN. Results Glomerulus HSPGs were stained bluish-green along the GBM with Alcian blue. However, IHC staining against agrin was almost completely negative in the lupus MGN group compared with the normal and non-lupus MGN groups, which showed brown staining of GBM. A higher level of anti-HS IgG was detected in LN compared with other groups, respectively. Higher titers were associated with the presence of SLE and nephritis. A higher degree of proteinuria normalized to glomerular filtration rate (eGFR) was observed in association with higher anti-HS antibody titers in LN. Conclusion This study demonstrated a functional loss of GBM HSPGs and higher levels of circulating anti-HS antibodies as a characteristic feature of lupus nephritis, suggesting their involvement in the pathogenesis of lupus nephritis and proteinuria.

Topics: Adult; Basement Membrane; Case-Control Studies; Enzyme-Linked Immunosorbent Assay; Female; Glomerular Filtration Rate; Glomerulonephritis, Membranous; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Humans; Immunoglobulin G; Kidney Glomerulus; Lupus Erythematosus, Systemic; Lupus Nephritis; Male; Middle Aged; Nephritis; Proteinuria; Young Adult

Recently we showed that antinuclear autoantibodies complexed to nucleosomes can bind to heparan sulphate (HS) in the glomerular basement membrane (GBM) via the histone part of the nucleosome. Histones have been identified in glomerular deposits in human and murine lupus nephritis. In addition, a decreased HS staining in the GBM was found, most probably due to masking by deposition of antibodies complexed to nucleosomes.. In this study we first investigated whether histones or nucleosomes could be identified in glomerular deposits in human lupus nephritis, and secondly whether the presence of these nuclear components was correlated with absence of HS staining. Kidney biopsies of SLE patients (11 with diffuse proliferative glomerulonephritis (DPGN) and six with membranous glomerulonephritis (MGN)) and non-SLE glomerular diseases were stained for histones. DNA, nucleosomes, IgG and HS.. Using a polyclonal anti-H3 1 21 antiserum, histones were detected in all patients with DPGN and in two of six patients with SLE-MGN (P < 0.01). Using a monoclonal antihistone antibody, histones were stained in three patients with DPGN, but in none of the biopsies with MGN. Using nucleosome specific monoclonal antibodies, nucleosomes were detected in five patients with DPGN, in two patients with MGN, but in none of the biopsies with non-SLE glomerulonephritis. HS staining was nearly absent in DPGN, whereas staining was only moderately reduced in patients with MGN and controls (P = 0.001).. Using polyclonal and monoclonal antihistone antisera, histones were identified in all patients with DPGN and their presence was associated with a decrease of HS staining. Nucleosomes were identified in five of 11 patients with DPGN and in two of six patients with MGN. This is the first demonstration of nucleosomes in glomerular deposits in SLE nephritis.

Topics: Adolescent; Adult; Animals; Antibodies, Monoclonal; Antigen-Antibody Complex; DNA; Female; Fluorescent Antibody Technique, Indirect; Glomerulonephritis, Membranoproliferative; Glomerulonephritis, Membranous; Heparitin Sulfate; Histones; Humans; Immunoglobulin G; Kidney Glomerulus; Lupus Nephritis; Male; Mice; Middle Aged; Nucleosomes

Membranous glomerulonephritis (MN) is characterized by the presence of subepithelial immune complexes and thickening of the glomerular basement membrane (GBM). Immune complexes are recognized as subepithelial electron-dense deposits (EDDs) by electron microscopy. We used immunogold electron microscopy to detect the GBM components--type IV collagen, heparan sulfate proteoglycan (HS-PG) and laminin--in thickened GBM, and studied the relationship between immune complexes and these GBM components. We demonstrate that the three major basement membrane components are distributed throughout the newly synthesized GBM. These findings suggest that type IV collagen, HS-PG, and laminin together comprise the spike-like structures and the newly synthesized GBM-like matrix in the thickened GBM of idiopathic MN and membranous lupus nephritis. The newly constructed matrix in the GBM appears to be composed of nearly normal GBM. In type IV collagen, the alpha 1-chain was rarely present on the newly synthesized basement membrane in the lamina rara externa, while alpha 3-chain was present on the subepithelial newly synthesized basement membrane. HS-PG was found within EDDs in membranous lupus nephritis. This suggests that anti-DNA antibody may cross-react with the HS-PG component of the GBM and thus form a subepithelial immune complex.

Topics: Adult; Aged; Antigen-Antibody Complex; Basement Membrane; Biopsy, Needle; Collagen; Female; Fluorescent Antibody Technique; Glomerulonephritis, Membranous; Heparitin Sulfate; Humans; Kidney Glomerulus; Laminin; Male; Microscopy, Immunoelectron; Middle Aged

Most glomerular pathologies are associated with alterations of the matrix compartment. Using reagents directed against the alpha 1/alpha 2 and alpha 3 chains of type IV collagen [alpha 1/alpha 2(IV), alpha 3(IV)], laminin, heparan sulphate proteoglycan (HPG), fibronectin, collagen I, and collagen III, we investigated the modifications of the glomerular matrix components in several human glomerular lesions compared with normal kidney. In type I membranous glomerulonephritis (MGN) (nine cases), we did not observe alterations in the matrix component distribution. In MGN types II and III (five cases), the spikes and chainettes were made of the alpha 3(IV) chain, laminin, and HPG, while the alpha 1/alpha 2(IV) chains were localized along the subendothelial side of the glomerular basement membrane (GBM). In focal and segmental glomerulosclerosis (six cases), fibronectin, alpha 1/alpha 2(IV) chains, laminin, and small amounts of interstitial collagens were detected within the collapsed capillary loops; the newly formed matrix material between the podocytes and the GBM contained the alpha 1/alpha 2(IV) chains, laminin, and HPG but not the alpha 3(IV) chain. In crescentic glomerulonephritis (six cases), fibronectin was the most abundant and, in purely cellular crescents, the unique component. A basement membrane-like network containing laminin, HPG, alpha 1/alpha 2(IV) chains, and interstitial collagens developed in a second step between the crescent cells. Interstitial collagens were present in the crescent framework, even when the integrity of Bowman's capsule was preserved.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Collagen; Extracellular Matrix Proteins; Fibronectins; Glomerulonephritis; Glomerulonephritis, Membranoproliferative; Glomerulonephritis, Membranous; Glomerulosclerosis, Focal Segmental; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Humans; Immunoenzyme Techniques; Kidney Glomerulus; Laminin; Proteoglycans

We measured the concentrations of urine glycosaminoglycans (GAG) by the modified dimethylmethylene blue method and the concentration of urine heparan sulfate (HS) by enzyme-linked immunosorbent assay (ELISA) in patients with various glomerular diseases. The GAG/creatinine(Crea) ratios in patients with IgA nephropathy (mean +/- SD, 0.31 +/- 0.056) and membranous nephropathy (0.41 +/- 0.115) were significantly greater than in healthy controls (0.18 +/- 0.045). Urine GAG/Crea ratios in minimal change nephrotic patients increased during remission (0.38 +/- 0.102) and decreased to normal values during the nephrotic stage (0.25 +/- 0.088). In contrast, urine HS/Crea ratios in patients with minimal change nephrotic syndrome decreased during remission (0.0069 +/- 0.0029) and increased markedly during the nephrotic period (0.047 +/- 0.0007 versus controls 0.0158 +/- 0.0046). Serial measurement in three minimal change nephrotic patients showed the similar change for the HS/Crea ratio and urine albumin excretion in the course of steroid therapy. The loss of HS from the glomerular basement membrane (GBM) may therefore be related to the pathogenesis of increased albumin excretion and measurement of urine HS excretion may be helpful for studying metabolism in renal disease, especially in patients with minimal change lesions.

Topics: Adult; Enzyme-Linked Immunosorbent Assay; Female; Glomerulonephritis, IGA; Glomerulonephritis, Membranous; Glycosaminoglycans; Heparitin Sulfate; Humans; Male; Methylene Blue; Nephrosis, Lipoid; Spectrophotometry; Urinalysis

The present study describes the development of membranous glomerulopathy (MGP) with high proteinuria in DZB rats exposed to mercuric chloride (HgCl2). IgG1 and IgG2a antibodies, eluted from glomeruli with subepithelial immune deposits, bind to the interface of the GBM and epithelial cells. High reactivity to GBM was demonstrated by ELISA and Western blotting, which could be absorbed for 30% by laminin or laminin-associated extracellular matrix components. No reactivity was found with type IV collagen, fibronectin, heparan sulfate proteoglycans, or tubular brush border antigens. Absorption to GBM removed the reactivity to renal antigens. Passively transferred eluted antibodies bind in a predominantly linear pattern along the GBM, causing focal ultrastructural transformations of the podocytes. These results suggest that this type of HgCl2-induced MGP, associated with epithelial cell injury and proteinuria, is caused by autoantibodies to basement membrane components which are located at the epithelial cell-basement membrane interface and may be involved in cell-matrix binding.

Topics: Animals; Antibody Specificity; Autoantibodies; Blotting, Western; Collagen; Complement C3; Complement C9; Complement Membrane Attack Complex; Cross Reactions; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Fibronectins; Glomerulonephritis, Membranous; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Immunoglobulin E; Immunoglobulin G; Immunoglobulin M; Immunohistochemistry; Kidney Glomerulus; Laminin; Mercuric Chloride; Microscopy, Electron; Proteinuria; Proteoglycans; Rats; Rats, Inbred Strains; Time Factors

The distribution of heparan sulphate proteoglycans (HSPG) has been investigated in normal human glomeruli, membranous glomerulonephritis, mesangial IgA disease, and anti-glomerular basement membrane disease. HSPG was localized using anti-bovine HSPG antibody and 10 nm gold-labelled secondary antibody on paraformaldehyde-fixed, Lowicryl K4M resin-embedded kidneys. HSPG was present in all glomeruli and there was a zonation of its distribution in that it was predominantly on the epithelial aspect of the glomerular basement membrane (GBM) and mesangium with little in the central regions of the mesangial matrix. In the cases of immune complex glomerulonephritis, no HSPG was found in the electron-dense deposits. These findings contrast with our previous studies using the same technique in which type IV collagen and fibronectin were found predominantly on the endothelial aspect of the GBM.

Topics: Adult; Aged; Aged, 80 and over; Basement Membrane; Chondroitin Sulfate Proteoglycans; Female; Glomerular Mesangium; Glomerulonephritis, IGA; Glomerulonephritis, Membranous; Glycosaminoglycans; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Humans; Kidney Glomerulus; Male; Middle Aged; Proteoglycans; Reference Values