Activation of diacylglycerol in cultured endothelial cells exposed
to cyclic strain.
Evans, Leigh, Lijubov Frenkel, Colleen M. Brophy, Oscar Rosales, Sai
Sudhaker, Guangdi Li, Wei Du, Bauer E. Sumpio.
Departments of Surgery and Medicine, Yale University School of
Medicine, New Haven, CT
APStracts 3:0301C, 1996.
Confluent bovine aortic 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 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 phosphatidylinositol (PI)
by PI-PLC. To determine the origin of the sustained DAG phase,
confluent bovine aortic EC were incubated with 1mCi/ml [14C]
myristate overnight and subjected to cyclic strain. There was a
decrease in PC and a corresponding increase in DAG at 10s and 250s,
suggesting PC hydrolysis with the generation of DAG at both an early
(10s) and late (250s) phase. [14C]phosphatidylethanol (PEt), a
specific product of 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. Increasing the
concentration of ethanol led to a consistent decrease in DAG.
Furthermore, when EC were pre-treated with 1% ethanol, the strain
-induced proliferative response was attenuated.
Received 29 February 1996; accepted in final form 15 September
1996.
APS Manuscript Number C110-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 November 1996