Lipid-induced changes in vascular smooth muscle cell membrane fluidity areassociated with DNA synthesis

In the present study, we examined whether changes in the membrane fluidity of vascular smooth muscle cells (VSMCs) alter their DNA synthesis. For this purpose, the membrane fluidity of the cells was modulated after treatment of VSMCs with 1,2-dioleoyl phosphatidylcholine (PC). Treatment of VSMCs wit h 1,2-dioleoyl PC-rich medium containing 10% heat-inactivated human serum a nd 3 mg/ml 1,2-dioleoyl PC for 24 h resulted in an increase in VSMC membran e fluidity at all temperatures from 15 degrees to 40 degrees C as well as a 51% inhibition of DNA synthesis, compared with untreated cells. Remarkably , enrichment of VSMCs with 1,2-dioleoyl PC/cholesterol-rich medium containi ng 10% human serum, 3 mg/ml 1,2-dioleoyl PC and 2 mg/ml cholesterol restore d both membrane fluidity and DNA synthesis to the levels of untreated cells . The present findings show an inverse association between increased membra ne fluidity and cellular DNA synthesis.