The effect of protein kinase C and its alpha subtype on human vascular smooth muscle cell proliferation, migration and fibronectin production

Background. Vascular smooth muscle cell (SMC) migration, proliferation and extracellular matrix protein production are key steps in the formation of i ntimal hyperplasia, a process that leads to failure of vascular reconstruct ions. Protein kinase C (PKC) may be involved in all 3 cellular events. PKC consists of a family of 11 isotypes, 8 of which we have identified in human vascular SMCs. In this study we evaluate the role of PKC alpha as a second messenger for proliferation, migration and fibronectin production induced by human saphenous vein SMCs. Methods. DNA synthesis was evaluated by using H-3-thymidine incorporation, Mitogen-activated protein Kinase (MAP-K) activation was quantified by Weste rn blotting with an antibody to its phosphorylated substrate, Elk-1. Chemot axis was evaluated by using a microchemotaxis chamber. SMC fibronectin was measured by Western blotting For all experiments, PKC alpha was blocked wit h a selective inhibitor, Go6976. Results, Go6976, at concentrations that allow selective inhibition of PKC a lpha, inhibited platelet-derived growth factor-stimulated SMC proliferation and MAP-K activation by 30 % to 40 % and 30 % to 60 %, respectively. SMC c hemotaxis was stimulated approximately 2-fold by the PKC alpha inhibitor Ne ither basal nor transforming growth factor-beta I induced fibronectin produ ction was affected by Go6976. Conclusions. Our data suggest that PKC alpha is a positive mediator of SMC proliferation and MAP-K activity, a negative regulator of migration and has no effect on SMC fibronectin production. These data suggest that modulatin g activities of specific PKC isotypes might be useful in both the study and control of intimal hyperplasia.