CREB-mediated IL-6 expression is required for 15(S)-hydroxyeicosatetraenoic acid-induced vascular smooth muscle cell migration.
OBJECTIVE
Migration of vascular smooth muscle cells (VSMCs) from media to intima is a key event in the pathophysiology of atherosclerosis and restenosis. The lipoxygenase products of polyunsaturated fatty acids (PUFA) were shown to play a role in these diseases. cAMP response element binding protein (CREB) has been implicated in the regulation of VSMC growth and motility in response to thrombin and angiotensin II. The aim of the present study was to test the role of CREB in an oxidized lipid molecule, 15(S)-HETE-induced VSMC migration and neointima formation.


RESULTS
15(S)-HETE stimulated VSMC migration in CREB-dependent manner, as measured by the modified Boyden chamber method. Blockade of MEK1, JNK1, or p38MAPK inhibited 15(S)-HETE-induced CREB phosphorylation and VSMC migration. 15(S)-HETE induced expression and secretion of interleukin-6 (IL-6), as analyzed by RT-PCR and ELISA, respectively. Neutralizing anti-IL-6 antibodies blocked 15(S)-HETE-induced VSMC migration. Dominant-negative mutant-mediated blockade of ERK1/2, JNK1, p38MAPK, or CREB suppressed 15(S)-HETE-induced IL-6 expression in VSMCs. Serial 5' deletions and site-directed mutagenesis of IL-6 promoter along with chromatin immunoprecipitation using anti-CREB antibodies showed that cAMP response element is essential for 15(S)-HETE-induced IL-6 expression. Dominant-negative CREB also suppressed balloon injury-induced IL-6 expression, SMC migration from media to intimal region, and neointima formation. Adenovirus-mediated transduction of 15-lipoxygenase 2 (15-LOX2) caused increased production of 15-HETE in VSMCs and enhanced IL-6 expression, SMC migration from media to intimal region, and neointima formation in response to arterial injury.


CONCLUSIONS
The above results suggest a role for 15-LOX2-15-HETE in the regulation of VSMC migration and neointima formation involving CREB-mediated IL-6 expression.
Chava
Koteswara R
KR
Department of Physiology, University of Tennessee Health Science Center, 894 Union Avenue, Memphis, TN 38163, USA.
Karpurapu
Manjula
M
Wang
Dong
D
Bhanoori
Manjula
M
Kundumani-Sridharan
Venkatesh
V
Zhang
Qiuhua
Q
Ichiki
Toshihiro
T
Glasgow
Wayne C
WC
Rao
Gadiparthi N
GN