ANG II stimulates phospholipase D through PKCzeta activation in VSMC: implications in adhesion, spreading, and hypertrophy.
ANG II stimulates phospholipase D (PLD) activity and growth of vascular smooth muscle cells (VSMC). The atypical protein kinase C-zeta (PKCzeta) plays a central role in the regulation of cell survival and proliferation. This study was conducted to determine the relationship between ANG II-induced activation of PKCzeta and PLD and their implication in VSMC adhesion, spreading, and hypertrophy. ANG II stimulated PKCzeta activity with maximal activation at 30 s followed by a decline in its activity to 45% above basal at 5 min. Inhibition of PKCzeta activity with a myristoylated pseudosubstrate peptide or overexpression of a kinase-inactive form of PKCzeta decreased ANG II-induced PLD activity. Moreover, depletion of PKCzeta with selective antisense oligonucleotides also decreased ANG II-induced PLD activity. Interaction between PLD2 and PKCzeta in VSMC was detected by coimmunoprecipitation. ANG II-induced PLD activity was inhibited by the primary alcohol n-butanol but not the tertiary alcohol t-butanol. The functional significance of PKCzeta and PLD2 in VSMC adhesion, spreading, and hypertrophy was investigated. Inhibition of PKCzeta and PLD2 activity or expression attenuated VSMC adhesion to collagen I and ANG II-induced cell spreading and hypertrophy. These results demonstrate that ANG II-induced PLD activation is regulated by PKCzeta and suggest a crucial role of PKCzeta-dependent PLD2 in VSMC functions such as adhesion, spreading, and hypertrophy, which are associated with the pathogenesis of atherosclerosis and malignant hypertension.
Parmentier
Jean-Hugues
JH
Dept. of Pharmacology, Crowe Bldg., The Univ. of Tennessee Health Science Center, Memphis, TN 38163, USA. jparmentier@utmem.edu
Pavicevic
Zoran
Z
Malik
Kafait U
KU
D020001:1-Butanol / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D004789:Enzyme Activation; D006984:Hypertrophy / Q000139:chemically induced / Q000503:physiopathology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000502:physiology*; D010739:Phospholipase D / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011493:Protein Kinase C / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000099221:Protein Kinase C zeta
D020001:1-Butanol; D000804:Angiotensin II; D010739:Phospholipase D; D011493:Protein Kinase C; D000099221:Protein Kinase C zeta