Effect of monensin on the sulfation of heparan sulfate proteoglycan from endothelial cells

Abstract

Monensin is a monovalent metal ionophore that affects the intracellular translocation of secretory proteins at the level of trans-Golgi cisternae. Exposure of endothelial cells to monensin results in the synthesis of heparan sulfate and chondroitin sulfate with a lower degree of sulfation. The inhibition is dose dependent and affects the ratio [35S]-sulfate/[3H]-hexosamine of heparan sulfate from both cells and medium, with no changes in their molecular weight. By the use of several degradative enzymes (heparitinases, glycuronidase, and sulfatases) the fine structure of the heparan sulfate synthesized by control and monensin-treated cells was investigated. The results have shown that among the six heparan sulfate disaccharides there is a specific decrease of the ones bearing a sulfate ester at the 6-position of the glucosamine moiety. All other biosynthetic steps were not affected by monensin. The results are indicative that monensin affects the hexosamine C-6 sulfation, and that this sterification is the last step of the heparan sulfate biosynthesis and should occur at the trans-Golgi compartment.

Interleukin-8 alters glomerular heparan sulfate glycosaminoglycan chain size and charge in rats

“…This study did not define which of the six known heparan sulfate disaccharide isomers obtained by heparitinase digestion were present. It is tempting to speculate that in IL8-infused rats, there is, as under other experimental conditions associated with low sulfation [16], a decrease in the disaccharides bearing a sulfate ester at the 6-position of the glucosamine moiety, since this esterification is the last step of heparan sulfate synthesis that seems to occur in the trans-Golgi compartment [17]. Further studies assessing the disaccharide composition of the altered heparan sulfate are needed to confirm this hypothesis.…”

Expression of a widely distributed, novel sulfated membrane glycoprotein by bovine endothelia and certain transporting epithelia.

“…Sensitivity of sulfation of gp4A4 in M monensin suggested that gp4A4 is a sulfated glycoprotein and not a proteoglycan (Sampaio et al, 1992). In addition, gp4A4 did not bind to an anion exchange resin in low salt concentrations (0.2 M NaCI), further suggesting that it is not a proteoglycan or a glycosaminoglycan (S.R.…”

“…The proteins were excised and extracted from the gel and the amount of radioactivity measured. Sulfation of gp4A4 was inhibited 70% by M monensin, which blocks sulfation of all sulfated glycoproteins and <15% by M monensin, which only inhibits sulfation of proteoglycans (Sampaio et al, 1992).…”

“…To determine ifgp4A4 was a proteoglycan, the effects of monensin on sulfation were examined (Sampaio et al, 1992). BMECs were pre-treated for 2 hr with monensin and then incubated for another 4 hr with monensin and Na2[3'S]04 and gp4A4 recovered by immunoprecipitation.…”

Development of an electrospun biomimetic polyurea scaffold suitable for vascular grafting

“…Endothelial cells act as an antithrombogenic surface since they inhibit platelet adhesion, fibrinolysis and clotting . Endothelial cells also serve as a source of molecules that act to minimize the migration of the SMCs into the luminal side of the graft, thereby, reducing IH . Independent of the migratory effects of these biomolecules, they prevent the attachment of platelets to the luminal surface of the graft promoting sustained hemocompatibility .…”