Reduction of anionic sites in the glomerular basement membrane by heparanase does not lead to proteinuria

Heparan sulfate in the glomerular basement membrane has been considered crucial for charge-selective filtration. In many proteinuric diseases, increased glomerular expression of heparanase is associated with decreased heparan sulfate. Here, we used mice overexpressing heparanase and evaluated the expression of different heparan sulfate domains in the kidney and other tissues measured with anti-heparan sulfate antibodies. Glycosaminoglycan-associated anionic sites were visualized by the cationic dye cupromeronic blue. Transgenic mice showed a differential loss of heparan sulfate domains in several tissues. An unmodified and a sulfated heparan sulfate domain resisted heparanase action in vivo and in vitro. Glycosaminoglycan-associated anionic sites were reduced about fivefold in the glomerular basement membrane of transgenic mice, whereas glomerular ultrastructure and renal function remained normal. Heparanase-resistant heparan sulfate domains may represent remnant chains or chains not susceptible to cleavage. Importantly, the strong reduction of glycosaminoglycan-associated anionic sites in the glomerular basement membrane without development of a clear renal phenotype questions the primary role of heparan sulfate in charge-selective filtration. We cannot, however, exclude that overexpression of heparanase and heparan sulfate loss in the basement membrane in glomerular diseases contributes to proteinuria.     

Molecular properties and involvement of heparanase in cancer progression and mammary gland morphogenesis

Tumor spread involves degradation of various components of the extracellular matrix and blood vessel wall. Among these is heparan sulfate proteoglycan, which plays a key role in the self-assembly, insolubility and barrier properties of basement membranes and extracellular matrices. Expression of an endoglycosidase (heparanase) which degrades heparan sulfate correlates with the metastatic potential of tumor cells, and treatment with heparanase inhibitors markedly reduces the incidence of metastasis in experimental animals. Heparin-binding angiogenic proteins are stored as a complex with heparan sulfate in the microenvironment of tumors. These proteins are released and can induce new capillary growth when heparan sulfate is degraded by heparanase. Here, we describe the molecular properties, expression and involvement in tumor progression of a human heparanase. The enzyme is synthesized as a latent 65 kDa protein that is processed at the N-terminus into a highly active 50 kDa form. The heparanase mRNA and protein are preferentially expressed in metastatic human cell lines and in tumor biopsy specimens, including breast carcinoma. Overexpression of the heparanase cDNA in low-metastatic tumor cells conferred a high metastatic potential in experimental animals, resulting in an increased rate of mortality. The heparanase enzyme also released ECM-resident bFGF in vitro, and its overexpression elicited an angiogenic response in vivo. Heparanase may thus facilitate both tumor cell invasion and neovascularization, two critical steps in tumor progression. Mammary glands of transgenic mice overexpressing the heparanase enzyme exhibit precocious branching of ducts and alveolar development, suggesting that the enzyme promotes normal morphogenesis and possibly pre-malignant changes in the mammary gland.     

Production of Heparan Sulfate in the Process of Calcium Oxalate Microlith Formation

To evaluate the interaction in the renal tubules between calcium oxalate microliths and glycosaminoglycans, especially heparan sulfate, we planned an experimentally–induced calcium oxalate microlith–producing model in rats. We found by immunofluorescence study and immunoelectron microscopy using the heparan sulfate antibody that heparan sulfate was produced in the renal tubular cells in the formation of calcium oxalate microliths and that heparan sulfate exists in the microliths. Heparan sulfate/crystal interaction might play a role as a nucleating agent and promote stone enlargement.     

Urinary Chondroitin Sulfates, Heparan Sulfate and Total Sulfated Glycosaminoglycans in Interstitial Cystitis

Purpose

We compared urinary glycosaminoglycan levels in patients with interstitial cystitis and healthy controls.

Materials and Methods

Total sulfated glycosaminoglycans assayed by dimethylmethylene blue binding and individual glycosaminoglycans analyzed by cellulose acetate electrophoresis were compared in patients with interstitial cystitis and healthy controls. Also, multiple urine samples were obtained from healthy female controls for 2 months to assess the relationship of urinary glycosaminoglycan and creatinine concentrations, and to determine whether glycosaminoglycan excretion changes during the menstrual cycle.

Results

Total sulfated glycosaminoglycan and creatinine concentrations correlated well in random voided samples. Menstrual cycle day did not affect total sulfated glycosaminoglycan levels. Cellulose acetate electrophoresis revealed 3 bands corresponding to chondroitin sulfates, heparan sulfate and acidic glycoprotein. Patients with interstitial cystitis had decreased urinary concentrations of each of these individual components and total sulfated glycosaminoglycans. However, glycosaminoglycan-to-creatinine ratios were similar in interstitial cystitis and control urine.

Conclusions

Using these assays total and individual urinary glycosaminoglycan levels normalized to creatinine were not altered in interstitial cystitis.     

Heparan sulfate proteoglycans in glomerular inflammation

Heparan sulfate proteoglycans (HSPGs) are glycoproteins consisting of a core protein to which linear heparan sulfate side chains are covalently attached. These heparan sulfate side chains can be modified at different positions by several enzymes, which include N-deacetylases, N- and O-sulfotransferases, and an epimerase. These heparan sulfate modifications give rise to an enormous structural diversity, which corresponds to the variety of biologic functions mediated by heparan sulfate, including its role in inflammation. The HSPGs in the glomerular basement membrane (GBM), perlecan, agrin, and collagen XVIII, play an important role in the charge-selective permeability of the glomerular filter. In addition to these HSPGs, various cell types express HSPGs at their cell surface, which include syndecans, glypicans, CD44, and betaglycan. During inflammation, HSPGs, especially heparan sulfate, in the extracellular matrix (ECM) and at the surface of endothelial cells bind chemokines, which establishes a local concentration gradient recruiting leukocytes. Endothelial and leukocyte cell surface HSPGs also play a role in their direct adhesive interactions via other cell surface adhesion molecules, such as selectins and beta2 integrin. Activated leukocytes and endothelial cells exert heparanase activity, resulting in degradation of heparan sulfate moieties in the ECM, which facilitates leukocyte passage into tissues and the release of heparan sulfate-bound factors. In various renal inflammatory diseases the expression of agrin and GBM-associated heparan sulfate is decreased, while the expression of CD44 is increased. Heparan sulfate or heparin preparations affect inflammatory cell behavior and have promising therapeutic, anti-inflammatory properties by preventing leukocyte adhesion/influx and tissue damage.     

肾癌乙酰肝素酶基因和蛋白表达的研究

目的实验证明乙酰肝素酶在多种恶性肿瘤中有高表达，并可能在恶性肿瘤细胞侵袭及转移中发挥重要作用。本研究探讨肾癌乙酰肝素酶基因和蛋白表达水平及其与肾癌发生、发展和转移的关系。方法应用荧光定量逆转录聚合酶链式反应和免疫组化Envision二步法分别检测30例新鲜肾癌和癌旁正常组织中乙酰肝素酶mRNA的表达水平及62例石蜡包埋肾癌组织中乙酰肝素酶蛋白的表达水平。结果乙酰肝素酶mRNA在肾癌中阳性表达11例（36．7％），乙酰肝素酶蛋白在肾癌中阳性表达15例（24．2％），其表达率与肿瘤的病理分级、临床分期和淋巴结转移有相关性（P〈0．05）。结论乙酰肝素酶基因和蛋白的异常表达可作为肾癌发生和发展的预后参数。     

Glycosaminoglycans of human prostatic cancer

The glycosaminoglycans of normal, benign hyperplastic and cancerous prostate were studied. In both prostatic hyperplasia and cancer the chondroitin sulfate:dermatan sulfate ratio was increased. In prostatic cancer this increase correlated with both the differentiation and extent of cancer in the prostate. The percentages heparan sulfate and heparan sulfate sulfation were decreased in prostatic cancer. Hyaluronic acid increased with dedifferentiation of the cancer. Histochemically, sulfated glycosaminoglycans were concentrated in the prostatic stroma at the stromal-epithelial interface. The increased chondroitin sulfate:dermatan sulfate ratio may be a nonspecific response or requirement for epithelial growth.     

膀胱肿瘤患者尿中葡萄糖氨基聚糖的研究

检测２３例膀胱肿瘤患者尿中的葡萄糖氨基聚糖（ＧＡＧｓ）。尿中的ＧＡＧｓ总量和硫酸软骨素含量与对照组比较无明显变化，但在高级别肿瘤患者，其尿中的ＨＳ明显升高，若肿瘤发生浸润，则ＨＳ、ＨＡ均明显升高，肿瘤切除后，尿中ＨＳ、ＨＡ恢复正常，当尿中ＨＳ排泄量超过１．６ｍｇ／ｄ，则肿瘤预后不良；ＨＡ排泄量超过０．８ｍｇ／ｄ时，则肿瘤已发生了浸润。     

Renal and urinary glycosaminoglycans in an experimental model of chronic renal failure in rats

The present paper reports the glomerular and renal individual glycosaminoglycan levels in an experimental model of chronic renal failure (CRF) that was induced in Wistar rats by five-sixths mass ablation. Glycemia, body weight, blood systolic pressure and urinary excretions of creatinine, albumin and glycosaminoglycans were measured for 12 weeks. At the end of the experiment, the weight and the glycosaminoglycan composition of the kidneys were determined. In control rats, heparan sulfate was the main glycosaminoglycan found both in whole kidney and isolated glomeruli, with trace amounts of dermatan sulfate. Isolated glomeruli presented higher heparan sulfate concentrations than whole kidney (expressed as mg/g dry weight). In CRF rats, albuminuria appeared from the 2 week on, and dermatan sulfate and chondroitin sulfate contents of the kidney increased, whereas heparan sulfate levels remained unaltered. Changes in urine glycosaminoglycans (heparan sulfate, chondroitin sulfate and dermatan sulfate) were not statistically significant. The increase in glomerular dermatan sulfate and chondroitin sulfate observed in this experimental model could be related to the mechanisms involved in the glomerulosclerosis and proteinuria that occur in CRF.     

Epidermal growth factor receptor gene analysis in renal cell carcinoma

The epidermal growth factor receptor binds the mitogens epidermal growth factor and transforming growth factor-alpha. Increased expression of the epidermal growth factor receptor has been noted in many types of tumors and is associated with gene amplification in several including epidermoid carcinoma, lung carcinoma, breast carcinoma and glioblastoma. We have recently observed increased expression of the epidermal growth factor receptor messenger RNA in neoplastic tissue relative to normal kidney tissue from patients with renal cell carcinoma. To determine if epidermal growth factor receptor gene amplification was present in renal cell carcinoma, DNA was extracted from renal cell carcinoma cell lines and from normal kidney and renal cell carcinoma tissues derived from radical nephrectomy specimens from thirty patients. DNA was analyzed by Southern blot hybridization. There was no epidermal growth factor receptor gene amplification detected in the renal cell carcinoma samples studied, indicating the increased epidermal growth factor gene expression observed in renal cell carcinoma does not occur through gene amplification. Unlike other tumors with enhanced epidermal growth factor receptor gene expression, amplification of this gene does not appear to be a common feature of renal cell carcinoma.     

The glycosaminoglycans of human bladder cancers of varying grade and stage

The glycosaminoglycans of four normal human bladders and fourteen bladder cancers were characterized and quantitated (after proteolytic extraction) by specific enzyme digestion, cellulose acetate electrophoresis and densitometry. Hyaluronic acid, heparan sulfate, dermatan sulfate and chondroitin sulfate were identified in both normal and cancerous bladders. Hyaluronic acid and dermatan sulfate were the major glycosaminoglycans of the normal epithelium/submucosa while heparan sulfate and dermatan sulfate were predominant in normal bladder muscle. Bladder cancer glycosaminoglycan content was influenced by the stage and grade of the neoplasm. Hyaluronic acid and dermatan sulfate tended to decrease and chondroitin sulfate to increase in infiltrating cancers, whereas a decrease in the percentage of heparan sulfate correlated closely with higher grade tumors. The bladder cancer glycosaminoglycan profile may be indicative of the tumor's invasive potential.     

Studies on urolithiasis. The histochemistry of the kidney tissues and stones from patients with urolithiasis

In this study, 17 kidney tissue specimens and 29 renal stones were obtained from patients with urolithiasis. Control kidney specimens were dissected from 7 individuals not suffering from urolithiasis. The tissue specimens were fixed with 1% cetylpiridinium chloride (CPC) in 10% formalin (for 24 hours at room temperature). Then the kidney tissue specimens were embedded in paraffin and stained with hematoxylin-eosin for general observation as well as histochemically for demonstration of complex carbohydrates. Also, stone specimens were embedded in epon and thin sections made by the mineral polishing specimen preparation, and stained along with the kidney tissues. For identifying individual acidic and neutral carbohydrates, the enzyme digestion was performed for some tissue sections prior to histochemical staining. The stone-forming kidney tissues, normal kidney tissues and urinary stones (calcium oxalate, mixed, struvite) contained some glycosaminoglycans and neutral glycoproteins, but uric acid stones and cystine stones did not. The results of digestion with enzymes indicated that calcium oxalate stone-forming kidney tissue contains heparitin (heparan) sulfate; mixed stone-forming tissue contains sialic acid, hyaluronic acid, chondroitin sulfate A, B, C and heparitin (heparan) sulfate; struvite stone-forming tissue contains sialic acid, hyaluronic acid, chondroitin sulfate A, C and heparitin (heparan) sulfate; and cystine stone-forming tissue contains sialic acid, chondroitin sulfate A, C and heparitin (heparan) sulfate. The stone organic matrix is classified into the amorphous and stratiform types. The amorphous type matrix contains chondroitin sulfate A, B, C and heparitin (heparan) sulfate, and the stratiform type matrix also contains sialic acid and hyaluronic acid. The stone-forming kidney tissues, normal kidney tissues and stones (calcium oxalate, mixed, struvite) contain an appreciable amount of alpha-D-glucose, alpha-D-mannose and beta-D-galactose, but the uric acid stones and cystine stones do not contain sugar residues. Since the specific glycosaminoglycan composition differed for kidneys of different mineral content and stones of different morphological type, we believe that some glycosaminoglycans in kidneys and amorphous type matrix might play the role of a nucleating agent, and that a stratiform type matrix encourages stone enlargement.     

Human heparanase: roles in invasion and metastasis of cancer

Heparanase, which is an extracellular matrix degradative enzyme, degrades heparan sulfate and heparan sulfate proteoglycans, which are chief components of extracellular matrix and vascular basement membrane. The gene structure of this enzyme was recently determined. The biological functions of this enzyme in vivo were as follows: 1) this enzyme accelerates cancer cell invasion and metastasis though the degradation of vascular basement membrane and extracellular matrix by cancer cells; 2) this enzyme releases and activates heparin-binding growth factors such as bFGF and VEGF from heparan sulfate proteoglycans, and induces angiogenesis; 3) the degradative products of heparan sulfate proteoglycans by this enzyme suppress the biological function of activated T-lymphocytes. Therefore, heparanase is thought to be a favorable molecule for acceleration of cancer invasion and metastasis. The expression of heparanase is strongly correlated with the metastasis of melanoma and fibrosarcoma. Thus, heparanase may play important roles in invasion and metastasis of cancer.     

Studies of cultured human fibroblasts in diabetes mellitus: changes in heparan sulfate.

The incorporation of [35S]sulfate into glycosaminoglycans was studied in cultures of normal and diabetic skin fibroblasts. Heparan sulfate was determined by column chromatography after enzymatic degradation of chondroitin sulfates and dermatan sulfate by chondroitinase ABE. Cultured skin fibroblasts from both insulin-dependent and noninsulin-dependent diabetics were found to have increased proportions of heparan sulfate in the media relative to the other sulfated glycosaminoglycans.     

A synthetic heparanase inhibitor reduces proteinuria in passive Heymann nephritis

The beta-D-endoglycosidase heparanase has been proposed to be important in the pathogenesis of proteinuria by acting to selectively degrade the negatively charged side chains of heparan sulfate proteoglycans (HSPG) within the glomerular basement membrane (GBM). A loss of the negatively charged HSPG may result in alteration of the permselective properties of the GBM, loss of glomerular epithelial and endothelial cell anchor points, and liberation of growth factors. This study examined the effect of PI-88, a sulfated oligosaccharide heparanase inhibitor, on renal function, glomerular ultrastructure, and proteinuria. Continuous PI-88 infusion at 25 mg/kg per d did not adversely affect animal behavior, growth, or GFR. Cortical tubular vacuolation, however, was observed by light microscopy, and GBM thickness was significantly reduced in these animals (P < 0.0002). Tissue distribution studies using [(35)S]-labeled PI-88 revealed high levels of radioactivity in the kidney after a single subcutaneous injection of 25 mg/kg, suggesting protracted accumulation; moreover, active PI-88 was detected in urine. In passive Heymann nephritis, PI-88 delivered as a continuous infusion at 25 mg/kg per d significantly reduced autologous-phase proteinuria, at day 14 (P < 0.009), in the absence of altered sheep antibody deposition, C5b-9 deposition, and circulating rat anti-sheep antibody titers. Glomerular vascular endothelial growth factor and fibroblast growth factor expression was unaffected by PI-88 administration. However, PI-88 administration significantly prevented glomerular HSPG loss as demonstrated by quantitative immunofluorescence studies (P < 0.0001) in the absence of altered agrin distribution. These data therefore confirm the importance of heparanase in the development of proteinuria.     

Chondroitinase-resistant sulfated glycosaminoglycans synthesized by cartilages of chick embryos and of newborn chickens and rats

Summary Biosynthesis of chondroitinase-resistant glycosaminoglycans as minor components was studied in the cartilages of chick embryos and of newborn chickens and rats. Sternal and knee cartilages were labeled in vitro with³⁵SO ₄ ²⁻ , and then³⁵S-labeled glycosaminoglycans were analyzed. In rats up to 2 weeks old, only one glycosaminoglycan could be detected as heparan sulfate. In the chick embryos and the newborn chickens, however, keratan sulfate as well as heparan sulfate could be detected. As chondroitinase-sensitive glycosaminoglycans, large amounts of both chondroitin 4- and 6-sulfates were synthesized in the chick cartilage, but the synthesis of chondroitin 6-sulfate could scarcely be seen in the rat cartilage. The results seem to indicate that the biosynthesis of keratan sulfate has some relation to that of chondroitin 6-sulfate.     

Heparan sulfate in the stone matrix and its inhibitory effect on calcium oxalate crystallization

Summary The nature of the soluble stone matrix and its possible role in urinary stone formation was studied. For this purpose we performed two-dimensional cellulose acetate membrane electrophoresis of the glycosaminoglycans (GAGs) which were contained in the soluble stone matrix, substances adsorbed onto calcium oxalate crystals in vitro (crystal surface binding substances, CSBS) and urinary macromolecules (UMMs). The main GAG in the soluble stone matrix and CSBS was found to be heparan sulfate, whereas the UMMs contained various GAGs usually seen in urine. An inhibition assay showed the soluble stone matrix to have the strongest inhibitory activity among these macromolecular substances when inhibitory activity was expressed in terms of uronic acid concentration. It is suggested that the main GAG in the soluble stone matrix consists of heparan sulfate, which has a strong inhibitory activity on calcium oxalate crystal growth and aggregation and constitutes part of the CSBS.     

尾加压素Ⅱ及其受体在人肾透明细胞癌组织中的表达及意义

目的：测定肾透明细胞癌中尾加压素Ⅱ（UⅡ）与其受体（UT-R）的表达量,以期探讨UⅡ与UT—R的表达在肾透明细胞癌发生中的临床意义。方法：对12例。肾透明细胞癌肿瘤组织通过免疫组化检测肾透明细胞癌组织和正常肾组织UⅡ蛋白的表达,并采用逆转录一多聚酶链式反应（RT—PCR）的方法测定肾透明细胞癌组织和正常肾组织UⅡ mRNA和UT-RmRNA的表达量。结果：肾透明细胞癌组织和正常肾组织中有uⅡ蛋白表达。RT-PCR结果显示肾透明细胞癌中UⅡmRNA的表达明显高于正常肾组织0．92±0．09和0．62±0．06（P〈0．01）。UT-R mRNA的表达明显高于正常肾组织0．28±0．01和0．16±0．03（P〈0．01）。结论：肾透明细胞癌中UⅡ和UT—RmRNA高表达提示UⅡ／UT系统可能与肾透明细胞癌的发生、发展有关,UⅡ可能通过自分泌或軎分泌的方式发挥作用。