Modulation of sulfated proteoglycan synthesis by bovine aortic endothelial cells during migration

The rates of 35S-sulfate incorporation into proteoglycan were compared in multi-scratch wounded and confluent cultures of bovine aortic endothelial cells to determine whether proteoglycan synthesis is altered as cells are stimulated to migrate and proliferate. Incorporation was found to be stimulated in a time-dependent manner, reaching maximal levels 44-50 h after wounding, as cells migrated into wounded areas of the culture dish. Quantitative autoradiography of 35S-sulfate-labeled single-scratch wounded cultures demonstrated a 2-4-fold increase in the number of silver grains over migrating cells near the wound edge when compared to cells remote from the wound edge. Furthermore, when cell proliferation was blocked by inhibition of DNA synthesis, the increase in 35S-sulfate incorporation into proteoglycan after wounding was unaffected. These data indicate that cell division is not required for the modulation of proteoglycan synthesis to occur after wounding. Characterization of the newly synthesized proteoglycan by ion-exchange and molecular sieve chromatography demonstrated that heparan sulfate proteoglycan constitutes approximately 80% of the labeled proteoglycan in postconfluent cultures, while after wounding, chondroitin sulfate proteoglycan and/or dermatan sulfate proteoglycan (CS/DSPG) increases to as much as 60% of the total labeled proteoglycan. These results suggest that CS/DSPG synthesis is stimulated concomitant with the stimulation of endothelial cell migration after wounding.