PLASMIN STIMULATES THE RELEASE OF DERMATAN SULFATE FROM VASCULAR SMOOTH-MUSCLE CELLS IN CULTURE

We investigated the effect of plasmin on the release of sulfated glycosaminoglycans (GAG) from cultured vascular smooth muscle cells. Confluent cultures of vascular smooth muscle cells from bovine aorta were labelled with [S-35]sulfate and incubated at 37-degrees-C for principally 60 min in a serum-free medium in the presence of plasmin. Plasmin at 10 mU/ml (approximately 2.7-mu-g/ml) and above significantly increased the release of [S-35]sulfate-labeled GAG (S-35-GAG) from the cell layer after a 60 min incubation. A time course study showed that plasmin at 10 mU/ml significantly increased the S-35-GAG release after 20 min and longer. However, plasminogen at 100 mU/ml and below did not cause a significant change of the S-35-GAG release after a 90 min incubation. A characterization of S-35-GAG revealed that plasmin increased both dermatan sulfate and the other S-35-GAG in the medium. Plasmin at 100 mU/ml enhanced the cell detachment significantly but only slightly. From these results, it was suggested that a endogenous thrombin inhibitor heparin cofactor II may be activated in the liquid phase by dermatan sulfate released from plasmin-stimulated vascular smooth muscle cells when the vascular is disrupted and plasma is exposed to extravessel.