Simvastatin modulates cytokine-mediated endothelial cell adhesion molecule induction: involvement of an inhibitory G protein.
Endothelial cell adhesion molecules (CAMs) E-selectin, ICAM-1, and VCAM-1 play variably important roles in immune-mediated processes. They are induced by the proinflammatory cytokines IL-1 and TNF-alpha, and NF-kappaB is required for the regulated expression of all three genes. Regulators of this pathway could potentially be potent immune modulators. We studied the effect of a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, simvastatin, on cytokine-induced expression of CAMs in HUVEC. Unexpectedly, pretreatment with simvastatin potentiated the induction of all three endothelial CAMs by IL-1 and TNF, but not LPS or PMA, as detected by flow cytometry. Northern blot analysis demonstrated an increase in steady state IL-1-induced E-selectin mRNA levels in cells pretreated with simvastatin. This was associated with an increase in nuclear translocation of NF-kappaB, as detected by EMSA. The effect of simvastatin was reversed by mevalonate and geranylgeranyl pyrophosphate but not squalene, indicating that an inhibitory prenylated protein is involved in endothelial responses to proinflammatory cytokines. Pertussis toxin mimicked the effect of simvastatin, and the G protein activator NaF inhibited the cytokine-induced expression of endothelial CAMs, indicating that a Gialpha protein is involved. These results demonstrate that cytokine-mediated activation of the endothelium, and specifically CAM induction, can be modulated by a heterotrimeric G protein-coupled pathway. This may represent a "basal tone" of endothelial inactivation, which can either be disinhibited or amplified, depending on the stimulus.
Sadeghi
M M
MM
Division of Cardiovascular Medicine and Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, CT 06536, USA.
Collinge
M
M
Pardi
R
R
Bender
J R
JR
D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects / Q000276:immunology; D015815:Cell Adhesion Molecules / Q000096:biosynthesis*; D002478:Cells, Cultured; D002784:Cholesterol / Q000096:biosynthesis; D016207:Cytokines / Q000502:physiology*; D004357:Drug Synergism; D019040:E-Selectin / Q000096:biosynthesis / Q000235:genetics; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology / Q000378:metabolism*; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000502:physiology; D016328:NF-kappa B / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology; D019821:Simvastatin / Q000494:pharmacology*; D012969:Sodium Fluoride / Q000494:pharmacology; D014471:Umbilical Veins; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis
D000276:Adjuvants, Immunologic; D015815:Cell Adhesion Molecules; D016207:Cytokines; D019040:E-Selectin; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D007375:Interleukin-1; D016328:NF-kappa B; D012333:RNA, Messenger; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D012969:Sodium Fluoride; D002784:Cholesterol; D019821:Simvastatin; D019206:GTP-Binding Protein alpha Subunits, Gi-Go