d-609 and Atherosclerosis

We previously found that phosphatidylcholine-specific phospholipase C (PC-PLC) was a key inducing element of atherosclerosis, and might negatively regulate human umbilical vein endothelial cell (HUVEC) autophagy. To further investigate the mechanism of PC-PLC action, we initially identified phosphatidylethanolamine binding protein 1 (PEBP1) as a binding partner of PC-PLC by using mass spectrometry (MS, MALDI-TOF/TOF). We found that PEBP1 positively regulated PC-PLC activity in HUVECs, and inhibition of PC-PLC by its inhibitor D609 suppressed PEBP1 expression dramatically. Moreover, both PC-PLC and PEBP1 negatively regulated HUVEC autophagy independently of mammalian target of rapamycin (mTOR). Furthermore, the PEBP1 level was elevated during the development of atherosclerosis, while D609 significantly decreased the upregulated PEBP1 level in apoE(-/-) mice.

Topics: Animals; Apolipoproteins E; Atherosclerosis; Autophagy; Bridged-Ring Compounds; Human Umbilical Vein Endothelial Cells; Humans; Mice; Mice, Inbred C57BL; Norbornanes; Phosphatidylethanolamine Binding Protein; Protein Binding; Thiocarbamates; Thiones; TOR Serine-Threonine Kinases; Type C Phospholipases

Atherosclerosis is considered to be a chronic inflammatory disease. Previous research has demonstrated that phosphatidylcholine-specific phospholipase C (PC-PLC) plays critical roles in various inflammatory responses. However, the association between PC-PLC and atherosclerosis is undetermined. Therefore, we sought to investigate whether PC-PLC was implicated in atherosclerosis.. Immunofluorescence analysis revealed an upregulation of PC-PLC in the aortic endothelium from apolipoprotein E-deficient (apoE(-/-)) mice. PC-PLC level and activity were also increased in human umbilical vein endothelial cells in response to oxidized low-density lipoprotein treatment. Pharmacological blockade of PC-PLC by D609 inhibited the progression of preexisting atherosclerotic lesions in apoE(-/-) mice and changed the lesion composition into a more stable phenotype. Using a combination of pharmacological inhibition, polyclonal antibodies, confocal laser scanning microscopy and Western blotting, we demonstrated that PC-PLC was required for endothelial expression of lectin-like oxidized low-density lipoprotein receptor-1. In addition, D609 treatment significantly decreased the aortic endothelial expression of the vascular cell adhesion molecule-1 and the intercellular adhesion molecule-1. Furthermore, inhibition of PC-PLC in human umbilical vein endothelial cells reduced the oxidized low-density lipoprotein induced expression of vascular cell adhesion molecule-1, intercellular adhesion molecule-1, and monocyte chemotactic protein-1.. Our data suggest that PC-PLC contributes to the progression of atherosclerosis.

Topics: Animals; Apolipoproteins E; Atherosclerosis; Bridged-Ring Compounds; Cells, Cultured; Chemokine CCL2; Disease Models, Animal; Disease Progression; Endothelium, Vascular; Humans; Intercellular Adhesion Molecule-1; Lipoproteins, LDL; Mice; Mice, Knockout; Norbornanes; Thiocarbamates; Thiones; Type C Phospholipases; Up-Regulation; Vascular Cell Adhesion Molecule-1

Monocyte chemoattractant protein-1 (MCP1) plays a key role in monocyte/macrophage infiltration to the sub-endothelial space of the blood vessel wall, which is a critical initial step in atherosclerosis. In this study, we examined the intracellular signaling pathway of IL-1beta-induced MCP1 expression using various chemical inhibitors. The pretreatment of a phosphatidylcholine (PC)-specific PLC (PC-PLC) inhibitor (D609), PKC inhibitors, or an NF-kapaB inhibitor completely suppressed the IL-1beta-induced MCP1 expression through blocking NF-gammaB translocation to the nucleus. Pretreatment with inhibitors of tyrosine kinase or PLD partially suppressed MCP1 expression and failed to block nuclear NF-kappaB translocation. These results suggest that IL-1beta induces MCP1 expression through activation of NF-kappaB via the PC-PLC/PKC signaling pathway.

Topics: Active Transport, Cell Nucleus; Aorta; Atherosclerosis; Bridged-Ring Compounds; Cell Nucleus; Cells, Cultured; Chemokine CCL2; Estrenes; Genistein; Humans; Interleukin-1beta; Myocytes, Smooth Muscle; NF-kappa B; Norbornanes; Phospholipases; Protein-Tyrosine Kinases; Pyrrolidinones; Recombinant Proteins; Signal Transduction; Thiocarbamates; Thiones