Protein kinase C-delta regulates migration and proliferation of vascular smooth muscle cells through the extracellular signal-regulated kinase 1/2.
BACKGROUND
Smooth muscle cell (SMC) migration and proliferation are early and crucial events in the pathogenesis of intimal hyperplasia, the primary cause of restenosis after vascular intervention. We tested the hypothesis that protein kinase C-delta (PKCdelta), a ubiquitously expressed intracellular protein kinase, regulates vascular SMC proliferation and migration.


METHODS
Exogenous PKCdelta was expressed in cultured SMCs via stable transfection or adenovirus-mediated gene transfer. Conversely, endogenous PKCdelta was inhibited by means of targeted gene deletion (gene knock-out). Cell proliferation and migration were determined by (3)H-thymidine incorporation and 24-well transwell assay, respectively.


RESULTS
We isolated and examined three A10 SMC lines in which PKCdelta was stably transfected. Compared with cells that were transfected with an empty vector, cells transfected with PKCdelta exhibited reduced ability to proliferate. Moreover, PKCdelta transfection inhibited SMC migration toward platelet-derived growth factor-BB. Similar inhibitory effects on proliferation and migration were also observed when PKCdelta was introduced into primary aortic SMCs via an adenoviral vector. Interestingly, SMCs isolated from PKCdelta knockout mice also displayed decreased chemotaxis and proliferation compared with PKCdelta(+/+) littermates, suggesting a complex yet critical role for PKCdelta. We studied the mitogen-activated protein kinase extracellular signal-regulated kinases (ERK) 1/2 as a possible signaling pathway for PKCdelta's inhibitory effect. PKCdelta overexpression diminished ERK1/2 activity. Molecular restoration of ERK activation reversed the inhibitory effect of PKCdelta on SMC proliferation and migration.


CONCLUSIONS
We demonstrate that although normal migration and proliferation is lessened in SMCs deficient in PKCdelta, its prolonged activation also diminishes those behaviors. This suggests a dual, critical role for PKCdelta in SMC proliferation and migration, and thus intimal hyperplasia and restenosis.
Liu
Bo
B
Department of Surgery, Division of Vascular Surgery, New York Presbyterian Hospital, Weill Medical College of Cornell University, New York, NY 10021, USA. bol2001@med.cornell.edu
Ryer
Evan Joseph
EJ
Kundi
Rishi
R
Kamiya
Kentaro
K
Itoh
Hiroyuki
H
Faries
Peter L
PL
Sakakibara
Kenji
K
Kent
K Craig
KC
D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D049109:Cell Proliferation; D007527:Isoenzymes; D051379:Mice; D018345:Mice, Knockout; D048052:Mitogen-Activated Protein Kinase 3 / Q000096:biosynthesis*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology / Q000473:pathology*; D011493:Protein Kinase C / Q000096:biosynthesis*; D064546:Protein Kinase C beta; D051381:Rats; D015398:Signal Transduction / Q000502:physiology
D007527:Isoenzymes; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D048052:Mitogen-Activated Protein Kinase 3