Differential Labelings Suggest Two Specific Phospholipid Subclass Hydrolysis Promoted by PDGF-BB in Vascular Smooth Muscle Cells.

We have used differential phospholipid subclass labelings performed with [3H]lyso PAF and [3H] myristic acid into vascular smooth muscle cells (vSMC) to characterize the subclasses of phospholipid substrates upon different stimulation times with platelet-derived growth factor (PDGF-BB). In cells labeled with [3H]lyso PAF, PDGF-BB induced a sustained hydrolysis of alkyl-PE. In contrast, in [3H]myristic acid-labeled cells, PDGF-BB promoted a rapid and transitory hydrolysis of diacyl-PC. This hydrolysis was concomitant with an synthesis of diglyceride (DG) and phosphatidic acid (PA). Thus, both diacyl-PC and alkyl-PE appear to be major targets in PDGF-BB stimulation of SMC. These results suggest that agonists could induce the hydrolysis of precise phospholipid subclasses leading to a new specificity into the signal transduction cascade.