A novel role for nitric oxide in the endogenous degradation of heparan sulfate during recycling of glypican-1 in vascular endothelial cells

Author： Mani Katrin Jönsson Mats Edgren Gudrun Belting Mattias Fransson Lars-Åke

Publisher： Oxford University Press

ISSN： 1460-2423

Source： Glycobiology, Vol.10, Iss.6, 2000-06, pp. : 577-586

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

We show here that the endothelial cell-line ECV 304 expresses the heparan sulfate proteoglycan glypican-1. The predominant cellular glycoform carries truncated side-chains and is accompanied by heparan sulfate oligosaccharides. Treatment with brefeldin A results in accumulation of a glypican proteoglycan with full-size side-chains while the oligosaccharides disappear. During chase the glypican proteoglycan is converted to partially degraded heparan sulfate chains and chain-truncated proteoglycan, both of which can be captured by treatment with suramin. The heparan sulfate chains in the intact proteoglycan can be depolymerized by nitrite-dependent cleavage at internally located N-unsubstituted glucosamine moieties. Inhibition of NO-synthase or nitrite-deprivation prevents regeneration of intact proteoglycan from truncated precursors as well as formation of oligosaccharides. In nitrite-deprived cells, formation of glypican proteoglycan is restored when NO-donor is supplied. We propose that, in recycling glypican-1, heparan sulfate chains are cleaved at or near glucosamines with unsubstituted amino groups. NO-derived nitrite is then required for the removal of short, nonreducing terminal saccharides containing these N-unsubstituted glucosamine residues from the core protein stubs, facilitating re-synthesis of heparan sulfate chains.