Ginkgolide B reduces LOX-1 expression by inhibiting Akt phosphorylation and increasing Sirt1 expression in oxidized LDL-stimulated human umbilical vein endothelial cells

PLoS One. 2013 Sep 17;8(9):e74769. doi: 10.1371/journal.pone.0074769. eCollection 2013.

Abstract

Oxidized low-density lipoprotein (ox-LDL) is an important risk factor in the development of atherosclerosis. LOX-1, a lectin-like receptor for ox-LDL, is present primarily on endothelial cells and upregulated by ox-LDL, tumor necrosis factor a, shear stress, and cytokines in atherosclerosis. Recent studies demonstrated that ginkgolide B, a platelet-activating factor receptor antagonist, has antiinflammatory and antioxidant effects on endothelial and nerve cells. The present study investigated the effects of ginkgolide B on LOX-1 expression and the possible mechanism of action. Our results showed that ginkgolide B inhibited LOX-1 and intercellular cell adhesion molecule-1 (ICAM-1) expression in ox-LDL-stimulated endothelial cells through a mechanism associated with the attenuation of Akt activation. Similar data were obtained by silencing Akt and LY294002. We also evaluated Sirt1 and nuclear factor erythroid 2-related factor 2 (Nrf2) expression. These molecules play a protective role in endothelial cell injury. The results showed that ginkgolide B increased Sirt1 expression in ox-LDL-treated cells. The inhibitory effects of ginkgolide B on LOX-1 and ICAM-1 expression were reduced in Sirt1 siRNA-transfected cells. Nrf2 expression was increased in ox-LDL-treated cells, and ginkgolide B downregulated Nrf2 expression. These results suggest that ginkgolide B reduces Nrf2 expression by inhibiting LOX-1 expression, consequently reducing oxidative stress injury in ox-LDL-stimulated cells. Altogether, these results indicate that the protective effect of ginkgolide B on endothelial cells may be attributable to a decrease in LOX-1 expression and an increase in Sirt1 expression in ox-LDL-stimulated endothelial cells, the mechanism of which is linked to the inhibition of Akt activation. Ginkgolide B may be a multiple-target drug that exerts protective effects in ox-LDL-treated human umbilical vein endothelial cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Gene Expression Regulation / drug effects*
  • Ginkgolides / pharmacology*
  • Human Umbilical Vein Endothelial Cells / drug effects*
  • Human Umbilical Vein Endothelial Cells / metabolism*
  • Humans
  • Lactones / pharmacology*
  • Lipoproteins, LDL / pharmacology
  • NF-E2-Related Factor 2 / genetics
  • Phosphorylation / drug effects
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Scavenger Receptors, Class E / genetics*
  • Sirtuin 1 / genetics*
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • Ginkgolides
  • Lactones
  • Lipoproteins, LDL
  • NF-E2-Related Factor 2
  • OLR1 protein, human
  • Scavenger Receptors, Class E
  • oxidized low density lipoprotein
  • ginkgolide B
  • Proto-Oncogene Proteins c-akt
  • p38 Mitogen-Activated Protein Kinases
  • Sirtuin 1