Induction of Transglutaminase 2 by a Liver X Receptor/Retinoic Acid Receptor α Pathway Increases the Clearance of Apoptotic Cells by Human Macrophages

Rationale: Liver X receptors (LXRs) are oxysterol-activated nuclear receptors that are involved in the control of cholesterol homeostasis and inflammatory response. Human monocytes and macrophages express high levels of these receptors and are appropriate cells to study the response to LXR agonists. Objective: The purpose of this study was to identify new LXR targets in human primary monocytes and macrophages and the consequences of their activation. Methods and Results: We show that LXR agonists significantly increase the mRNA and protein levels of the retinoic acid receptor (RAR)α in primary monocytes and macrophages. LXR agonists promote RARα gene transcription through binding to a spec…