Endocrine Abstracts

The Liver X Receptors (LXRs) are members of the nuclear hormone receptor superfamily and play a key role as intracellular cholesterol sensors. LXRs control the expression of crucial genes associated with cholesterol absorption, excretion and efflux and are therefore key determinants of atherosclerosis susceptibility. In addition, recent studies have revealed the existence of crosstalk between macrophage inflammatory pathways and LXR signaling. In activated macrophages, LXR agonists inhibit the expression of inflammatory genes such as iNOS and IL-6 through different mechanisms, including interference with NF-kB signaling and induction of anti-inflammatory genes. Since macrophages are essential modulators of lipid metabolism and immune pathways, these results have important implications for the pharmaceutical control of inflammation and the pathogenesis of atherosclerosis. Collectively, these observations position LXRs at the crossroads of lipid metabolism and inflammatory signaling and suggest that these receptors may serve to integrate these pathways in the control of macrophage gene expression. In this meeting, we will summarize the recent discoveries in LXR biology as well as novel regulated genes by LXR in macrophages and other metabolic tissues.