Human coronary arterial SMCs were cultured in?vitro. Boyden microchemotaxis assays of migration were performed in response to S-1-P in the presence and absence the src inhibitor (PP2, 10 ¦ÌM) and a dominant negative src construct (DNsrc). siRNA to S-1-P receptors was used to down-regulate the S-1-P receptors. Western blotting was performed for src and MAPK phosphorylation.
Inhibition of src with PP2 but not PP3 partially blocked S-1-P-mediated cell migration. S-1-P induced time-dependent activation of src, which was inhibited by PP2 and adenoviral DNsrc. PP3 or an empty vector had no effect. Activation of src by S-1-P was inhibited by siRNA to S-1-PR1 and S-1-PR3 but not by S-1-PR2. When the VSMC were transfected with adenovirus containing ¦ÂARKCT, an inhibitor to G¦Â¦Ã, src activation was significantly attenuated. Src inhibition with PP2 reduced p38MAPK and JNK activation but did not alter ERK1/2 activation.
S-1-P mediated VSMC migration is modulated by a G-protein-coupled src pathway partially through src-mediated p38MAPK and JNK signaling and requires S-1-PR1 and S-1-PR3 receptors.