LXR is crucial in lipid metabolism.
Liver X receptors (LXRalpha and LXRbeta) are members of the nuclear receptor superfamily and are activated by oxysterols and intermediates in the cholesterol synthetic pathway. The pivotal role of LXRs in the metabolic conversion of cholesterol to bile acids is well established. Analysis of gene expression in LXRalpha and LXRbeta deficient mice have confirmed that LXR regulates a number of target genes involved in both cholesterol and fatty acid metabolism in liver, macrophages and intestine. The observation that LXRalpha is responsive to fatty acids and is expressed in metabolic tissues suggests that it also plays a general role in lipid metabolism. Adipose tissue is the main storage site for fat in the body and plays a crucial role in overall lipid handling. Both LXRalpha and LXRbeta are expressed and activated by endogenous and synthetic ligands, which lead to lipid accumulation into adipocytes. This indicates an important regulatory role of LXR in several metabolic signaling pathways in the adipose tissue, such as glucose uptake and de novo fatty acid synthesis. Here, we review recent studies that provide new insights into the mechanisms by which LXRs act to influence fatty acid synthesis in liver and adipose tissue.
Ulven
Stine Marie
SM
Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1046 Blindern, N-0316 Oslo, Norway.
Dalen
Knut Tomas
KT
Gustafsson
Jan-Ake
JA
Nebb
Hilde Irene
HI
D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D002784:Cholesterol / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D006801:Humans; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism*; D000071518:Liver X Receptors; D057093:Orphan Nuclear Receptors; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; D005227:Fatty Acids; D000071518:Liver X Receptors; C000605213:NR1H3 protein, human; C000605214:Nr1h3 protein, mouse; D057093:Orphan Nuclear Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D002784:Cholesterol