J. Biol. Chem., Vol. 261, Issue 17, 7611-7614, 06, 1986
Herpesvirus infection prevents activation of cytoplasmic cholesteryl esterase in arterial smooth muscle cells
DP Hajjar
Herpesvirus infection has been shown to alter the cholesteryl ester cycle
in avian arterial smooth muscle cells, resulting in cytoplasmic cholesteryl
ester accumulation (Hajjar, D. P., Falcone, D. J., Fabricant, C. G., and
Fabricant, J. (1985) J. Biol. Chem. 260, 6124- 6128). In this study, we
attempted to define some of the regulatory mechanisms associated with the
control of cytoplasmic cholesteryl esterase in Marek's disease herpesvirus
(MDV)-infected cells. We found that cholesteryl esterase activity in
MDV-infected cells could not be activated by dibutyryl cyclic AMP,
dibutyryl cyclic AMP added together with protein kinase, or agonists of
adenylate cyclase. Activation of cytoplasmic cholesteryl esterase activity
occurred in uninfected cells and in cells infected with a control virus,
turkey herpesvirus. Furthermore, the rate of cholesterol efflux from
arterial smooth muscle cells challenged with dibutyryl cyclic AMP was
unchanged in MDV- infected cells as compared to uninfected or turkey
herpesvirus-infected cells in which efflux was increased. We propose that
the reduced cytoplasmic cholesteryl esterase activity in lipid-laden,
herpesvirus- infected cells is due partly to its inability to be activated
by the cyclic AMP-protein kinase mechanism. This may contribute to the
pathologic changes seen in MDV-infected arterial cells, including
accumulation of intracellular cholesteryl esters.