SRC regulates sphingosine-1-phosphate mediated smooth muscle cell migration.

Area of Science:

• Cellular signaling and molecular biology
• Vascular biology and smooth muscle cell function
• Biochemistry of lipid mediators

Background:

• Sphingosine-1-phosphate (S-1-P) is a lipid mediator released at arterial injury sites.
• S-1-P stimulates smooth muscle cell (SMC) migration.
• The src kinase is a key component of transmembrane signaling pathways.

Purpose of the Study:

• To investigate the role of the src kinase in S-1-P-induced SMC migration.
• To elucidate the specific S-1-P receptors involved in this process.
• To understand the downstream signaling events mediated by src.

Main Methods:

• Human coronary arterial SMCs were utilized in vitro.
• Boyden microchemotaxis assays assessed cell migration.
• src inhibition was achieved using PP2 (inhibitor) and DNsrc (dominant-negative construct).
• S-1-P receptor function was modulated using siRNA, and Western blotting detected protein phosphorylation.

Main Results:

• Inhibition of src partially blocked S-1-P-mediated SMC migration.
• S-1-P induced time-dependent src activation, dependent on S-1-PR1 and S-1-PR3 receptors.
• Src activation was attenuated by inhibiting Gβγ signaling.
• Src inhibition affected p38 MAPK and JNK activation but not ERK1/2.

Conclusions:

• S-1-P-mediated SMC migration is regulated by a G-protein-coupled src pathway.
• This pathway involves src-mediated p38 MAPK and JNK signaling.
• S-1-PR1 and S-1-PR3 receptors are essential for S-1-P-induced migration.