Xenoreceptors CAR and PXR activation and consequences on lipid metabolism, glucose homeostasis, and inflammatory response

Xenobiotic and drug metabolism and transport are managed by a large number of genes coordinately regulated by at least three nuclear receptors or xenosensors: aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR, NR1 |3), and pregnane X receptor (PXR, NR1 12). Initially characterized as xenosensors, it is now evident that CAR and PXR also trigger pleiotropic effects on liver function. Recent studies have shown the existence of crosstalk between xenosensors and other nuclear receptors or transcription factors controlling endogenous signaling pathways which regulate physiological functions. This review is focused on recent observations showing that activation of CAR and PXR alters lipid metabolism, glucose homeostasis, and inflammation by interfering with HNF4 alpha, FoxO1, FoxA2, PGC1 alpha, or NFkB p65. Such crosstalks explain clinical observations and provide molecular mechanisms allowing understanding how xenobiotics and drugs may affect physiological functions and provoke endocrine disruptions.