[Glycosaminoglycan-glomerular basement membrane interactions revealed by affinity chromatography (author's transl)]

Abstract

Glycosaminoglycans (GAG) are major constituents of the extracellular matrix of the kidney and an integral part of the glomerular basement membrane (GBM). To elucidate the nature of the interaction between these structures we performed binding studies applying affinity chromatography. Solubilized glomerular basement membranes were coupled to the gel and the binding of heparan sulfate (HS), heparin (H), chondroitin-4-sulfate (Ch-4-S) and hyaluronic acid (HA) was studied, HS and H bound strongly to the glomerular basement membrane eluting with 4 M urea and 3 M NaCl on contrary to chondroitin-4-sulfate and hyaluronic acid which did not bind in our system. In order to determine which component of the GBM is responsible for the binding of the GAG we studied the linkage between basement membrane collagen type IV and laminin with the GAG. Both substances reflected the binding activity of their matrix substance for HS and H, but presenting low binding affinity for Ch-4-S reversible with 4 M urea and 1 M NaCl. The binding of the highly charged GAG could play an important role in physiological and pathophysiological functions with special regard to glomerular filtration processes.