Role of NF-kappaB in regulation of PXR-mediated gene expression: a mechanism for the suppression of cytochrome P-450 3A4 by proinflammatory agents. Academic Article uri icon

abstract

  • It is a long-standing observation that inflammatory responses and infections decrease drug metabolism capacity in human and experimental animals. Cytochrome P-450 3A4 cyp304 is responsible for the metabolism of over 50% of current prescription drugs, and cyp3a4 expression is transcriptionally regulated by pregnane X receptor (PXR), which is a ligand-dependent transcription factor. In this study, we report that NF-kappaB activation by lipopolysaccharide and tumor necrosis factor-alpha plays a pivotal role in the suppression of cyp3a4 through interactions of NF-kappaB with the PXR.retinoid X receptor (RXR) complex. Inhibition of NF-kappaB by NF-kappaB-specific suppressor SRIkappaBalpha reversed the suppressive effects of lipopolysaccharide and tumor necrosis factor-alpha. Furthermore, we showed that NF-kappaB p65 disrupted the association of the PXR.RXRalpha complex with DNA sequences as determined by electrophoretic mobility shift assay and chromatin immunoprecipitation assays. NF-kappaB p65 directly interacted with the DNA-binding domain of RXRalpha and may prevent its binding to the consensus DNA sequences, thus inhibiting the transactivation by the PXR.RXRalpha complex. This mechanism of suppression by NF-kappaB activation may be extended to other nuclear receptor-regulated systems where RXRalpha is a dimerization partner.

published proceedings

  • J Biol Chem

altmetric score

  • 3

author list (cited authors)

  • Gu, X., Ke, S., Liu, D., Sheng, T., Thomas, P. E., Rabson, A. B., ... Tian, Y.

citation count

  • 256

publication date

  • June 2006