Effects of oxLDL and simvastatin on PKC activity and level of cytosolic free Ca~(2+) in cultured human umbilical vein endothelial cells / 第二军医大学学报

ABSTRACT

Objective: To investigate the effects of oxLDL and HMG CoA reductase inhibitor simvastatin on PKC activity, and level of cytosolic free Ca 2+ in cultured human umbilical vein endothelial cells. Methods: The activity of PKC was determined by its ability to transfer phosphate from 32 P ATP to lysine rich histone and level of cytosolic free calcium[Ca 2+ ]i was measured by flow cytometric analysis loading with the Ca 2+ dye Fluo 3/Am. Results: oxLDL increased PKC total activity in a dose dependent manner and peaked after 12 min, then decreased slowly and maintained for at least 30 min, while oxLDL induced biphasic [Ca 2+ ]i responses including the rapid initial transient phase and the sustained phase. Removal of extracellular Ca 2+ did not inhibit the rapid transient phase, but abolished the sustained phase. When simvastatin was added, the activity of PKC wasmarkedly decreased with no impairment to the initial peak response, but significantly reduced the sustained phase. Conclusion: oxLDL can induced dynamic changes of signal transduction of PKC and level of cytosolic free Ca 2+ in HUVEC, these 2 events are closely linked. The change of rapid initial transient phase is the result of mobilization of Ca 2+ from intracellular pool and the change of sustained phase is from the influx of extracellular Ca 2+ . The inhibition of PKC activity induced by simvastatin may contribute to the changes of [Ca 2+ ]i. [