Subject:
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IGMD 3: Genomic disorders and inherited multi-system disorders IGMD 8: Mitochondrial medicine IGMD 9: Renal disorder N4i 4: Auto-immunity, transplantation and immunotherapy NCMLS 1: Immunity, infection and tissue repair NCMLS 1: Infection and autoimmunity NCMLS 3: Tissue engineering and pathology NCMLS 4: Energy and redox metabolism ONCOL 3: Translational research UMCN 1.2: Molecular diagnosis, prognosis and monitoring UMCN 4.2: Chronic inflammation and autoimmunity UMCN 5.4: Renal disorders |
Organization:
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Nephrology Biochemistry (UMC) Pathology Paediatrics - OUD tm 2017 |
Journal title:
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Kidney International. Supplement
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Abstract:
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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.
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