12/15-lipoxygenase regulates intercellular adhesion molecule-1 expression and monocyte adhesion to endothelium through activation of RhoA and nuclear factor-kappaB.
BACKGROUND
12/15-lipoxygenase (12/15-LO) activity leads to the production of the proinflammatory eicosanoids 12-S-hydroxyeicosatetraenoic acid (12SHETE) and 13-S-hydroxyoctadecadienoic acid. We have previously shown a 3.5-fold increase in endothelial intercellular adhesion molecule (ICAM)-1 expression in mice overexpressing the 12/15-LO gene. We examined whether 12/15-LO activity regulated endothelial ICAM-1 expression.


RESULTS
Freshly isolated aortic endothelial cells (EC) from 12/15-LO transgenic mice had significantly greater nuclear factor-kappaB (NF-kappaB) activation and ICAM mRNA expression compared with C57BL/6J control. 12/15-LO transgenic EC showed elevated RhoA activity, and inhibition of RhoA using either C3 toxin or the Rho-kinase inhibitor Y-27632 blocked NF-kappaB activation, ICAM-1 induction, and monocyte adhesion. Furthermore, we show that 12SHETE activates protein kinase Calpha, which forms a complex with active RhoA and is required for NF-kappaB-dependent ICAM expression in response to 12SHETE.


CONCLUSIONS
The 12/15-LO pathway stimulates ICAM-1 expression through the RhoA/protein kinase Calpha-dependent activation of NF-kappaB. These findings identify a major signaling pathway in EC through which 12/15-LO contributes to vascular inflammation and atherosclerosis.
Bolick
David T
DT
Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA.
Orr
A Wayne
AW
Whetzel
Angela
A
Srinivasan
Suseela
S
Hatley
Melissa E
ME
Schwartz
Martin A
MA
Hedrick
Catherine C
CC
D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000166:cytology; D001092:Arachidonate 12-Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D001093:Arachidonate 15-Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D050197:Atherosclerosis / Q000378:metabolism / Q000503:physiopathology; D002448:Cell Adhesion / Q000276:immunology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009000:Monocytes / Q000166:cytology*; D016328:NF-kappa B / Q000378:metabolism; D051571:Protein Kinase C-alpha / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology; D014657:Vasculitis / Q000378:metabolism* / Q000503:physiopathology; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
C475064:12-15-lipoxygenase; D016328:NF-kappa B; D018799:Intercellular Adhesion Molecule-1; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D001092:Arachidonate 12-Lipoxygenase; D001093:Arachidonate 15-Lipoxygenase; D051571:Protein Kinase C-alpha; D020742:rhoA GTP-Binding Protein