LXRα

Liver X receptor alpha (LXRα; NR1H3) is a ligand-activated nuclear receptor that functions as a cellular cholesterol sensor and transcriptional regulator of lipid homeostasis, particularly in metabolically active tissues such as liver, intestine, adipose tissue, and macrophages^[1][2]. Mechanistically, LXRα forms heterodimers with retinoid X receptor (RXR) and activates gene networks that promote cholesterol efflux, transport, and elimination, thereby maintaining intracellular cholesterol balance^[1][3]. LXRα signaling also regulates reverse cholesterol transport through induction of ATP-binding cassette transporters, linking sterol sensing to systemic lipid metabolism^[1]. In metabolic disease models, LXRα is required for maintenance of hepatic cholesterol homeostasis, and impaired LXRα activity leads to hepatic cholesterol accumulation, inflammation, hepatitis, and fibrosis, highlighting its importance in liver health and metabolic regulation^[4]. Compared with the related isoform LXRβ (NR1H2), which is expressed ubiquitously across tissues, LXRα exhibits a more restricted expression pattern and is the dominant LXR isoform in hepatocytes, indicating distinct physiological functions despite overlapping target pathways^[2][5]. LXRα expression is further regulated through an autoregulatory mechanism in macrophages and other cell types, which can amplify transcriptional responses to endogenous oxysterol ligands^[6][7]. For experimental applications, synthetic LXR agonists such as T0901317 are widely used to activate LXR-dependent transcriptional programs and investigate cholesterol metabolism, lipid synthesis, and nuclear receptor signaling pathways^[5].