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Research Letters in Biochemistry
Volume 2008 (2008), Article ID 801849, 5 pages
Research Letter

Liver X Receptor Agonists Inhibit the Phospholipid Regulatory Gene CTP: Phosphoethanolamine Cytidylyltransferase-Pcyt2

Department of Human Health and Nutritional Sciences, University of Guelph, Ontario, N1G 2W1, Canada

Received 27 February 2008; Accepted 7 April 2008

Academic Editor: David Brindley

Copyright © 2008 Lin Zhu and Marica Bakovic. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Metabolic pulse-chase experiments demonstrated that 25-hydroxycholesterol (25-OH), the endogenous activator of the liver X receptor (LXR), significantly reduced the biosynthesis of phosphatidylethanolamine via CDP-ethanolamine (Kennedy) pathway at the step catalyzed by CTP: phosphoethanolamine cytidylyltransferase (Pcyt2). In the mouse embryonic fibroblasts C3H10T1/2, the LXR synthetic agonist TO901317 lowered Pcyt2 promoter-luciferase activity in a concentration-dependent manner. Furthermore, 25-OH and TO901317 reduced mouse Pcyt2 mRNA and protein levels by 35–60%. The inhibitory effects of oxysterols and TO901317 on the Pcyt2 promoter function, mRNA and protein expression were conserved in the human breast cancer cells MCF-7. These studies identify the Pcyt2 gene as a novel target whereby LXR agonists may indirectly modulate inflammatory responses and atherosclerosis.