title: Activation of diacylglycerol in cultured endothelial cells exposed to cyclic strain.
abstract: Confluent bovine aortic endothelial cells (EC) were grown on flexible membranes and subjected to 10% average strain at 60 cycles/min for up to 500 s. A biphasic increase in diacylglycerol (DAG) occurred, with an initial transient peak at 10 s followed by sustained elevation to 500 s. The early peak corresponded to the transient formation of inositol 1,4,5-trisphosphate, demonstrating hydrolysis of L-alpha-phosphatidylinositol (PI) by PI-specific phospholipase C. To determine the origin of the sustained DAG phase, we incubated confluent bovine aortic EC with 1 microCi/ml [14C]myristate overnight and subjected them to cyclic strain. There was a decrease in phosphatidylcholine (PC) and a corresponding increase in DAG at 10 s and 250 s, suggesting PC hydrolysis with the generation of DAG at both an early (10 s) and a late (250 s) phase. [14C]phosphatidylethanol, a specific product of phospholipase D (PLD) in the presence of 1% ethanol, was measured in EC preincubated with [14C]myristate. Cyclic strain led to an immediate and sustained activation of PLD. Increased ethanol concentration led to a consistent decrease in DAG. Furthermore, when EC were pretreated with 1% ethanol, the strain-induced proliferative response was attenuated.
authors.affiliation: Department of Surgery, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
authors.forename: L
authors.initials: L
authors.lastname: Evans
authors.forename: L
authors.initials: L
authors.lastname: Frenkel
authors.forename: C M
authors.initials: CM
authors.lastname: Brophy
authors.forename: O
authors.initials: O
authors.lastname: Rosales
authors.forename: C B
authors.initials: CB
authors.lastname: Sudhaker
authors.forename: G
authors.initials: G
authors.lastname: Li
authors.forename: W
authors.initials: W
authors.lastname: Du
authors.forename: B E
authors.initials: BE
authors.lastname: Sumpio
mesh_terms: D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D004075:Diglycerides / Q000096:biosynthesis*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology; D006868:Hydrolysis; D010507:Periodicity; D010713:Phosphatidylcholines / Q000378:metabolism; D013314:Stress, Mechanical; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors
chemical_list: D004075:Diglycerides; D010713:Phosphatidylcholines; D000431:Ethanol; D013936:Thymidine