Promoter DNA methylation of farnesoid X receptor and pregnane X receptor modulates the intrahepatic cholestasis of pregnancy phenotype

PLoS One. 2014 Jan 31;9(1):e87697. doi: 10.1371/journal.pone.0087697. eCollection 2014.

Abstract

The intrahepatic cholestasis of pregnancy (ICP) is a multifactorial liver disorder which pathogenesis involves the interplay among abnormal bile acid (BA) levels, sex hormones, environmental factors, and genetic susceptibility. The dynamic nature of ICP that usually resolves soon after delivery suggests the possibility that its pathobiology is under epigenetic modulation. We explored the status of white blood peripheral cells-DNA methylation of CpG-enriched sites at the promoter of targeted genes (FXR/NR1H4, PXR/NR1I2, NR1I3, ESR1, and ABCC2) in a sample of 88 ICP patients and 173 healthy pregnant women in the third trimester of their pregnancies. CpG dinucleotides at the gene promoter of nuclear receptors subfamily 1 members and ABCC2 transporter were highly methylated during healthy pregnancy. We observed significant differences at the distal (-1890) and proximal promoter (-358) CpG sites of the FXR/NR1H4 and at the distal PXR/NR1I2 (-1224) promoter, which were consistently less methylated in ICP cases when compared with controls. In addition, we observed that methylation at FXR/NR1H4-1890 and PXR/NR1I2-1224 promoter sites was highly and positively correlated with BA profiling, particularly, conjugated BAs. Conversely, methylation level at the proximal FXR/NR1H4-358 CpG site was significantly and negatively correlated with the primary cholic and secondary deoxycholic acid. In vitro exploration showed that epiallopregnanolone sulfate, a reported FXR inhibitor, regulates the transcriptional activity of FXR/NR1H4 but seems to be not involved in the methylation changes. In conclusion, the identification of epigenetic marks in target genes provides a basis for the understanding of adverse liver-related pregnancy outcomes, including ICP.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cell Line, Tumor
  • Cholestasis, Intrahepatic / genetics
  • Cholestasis, Intrahepatic / metabolism*
  • Cholestasis, Intrahepatic / pathology
  • Constitutive Androstane Receptor
  • DNA Methylation*
  • Epigenesis, Genetic / drug effects
  • Epigenesis, Genetic / genetics
  • Female
  • Humans
  • Male
  • Multidrug Resistance-Associated Protein 2
  • Phenotype*
  • Pregnancy
  • Pregnancy Complications / genetics
  • Pregnancy Complications / metabolism*
  • Pregnancy Complications / pathology
  • Pregnanolone / analogs & derivatives
  • Pregnanolone / pharmacology
  • Promoter Regions, Genetic*
  • Receptors, Cytoplasmic and Nuclear / genetics
  • Receptors, Cytoplasmic and Nuclear / metabolism*
  • Transcription, Genetic / drug effects
  • Transcription, Genetic / genetics

Substances

  • ABCC2 protein, human
  • Constitutive Androstane Receptor
  • Multidrug Resistance-Associated Protein 2
  • NR1I3 protein, human
  • Receptors, Cytoplasmic and Nuclear
  • epiallopregnanolone sulfate
  • farnesoid X-activated receptor
  • Pregnanolone

Supplementary concepts

  • Intrahepatic Cholestasis of Pregnancy

Grants and funding

Supported in part by Grants UBACYT CM04 (Universidad de Buenos Aires), PICT 2008-1521 and PICT 2010-0441 (Agencia Nacional de Promoción Científica y Tecnológica), and Consejo de Investigación en Salud del Gobierno de la Ciudad Autonóma de Bs. As.SS, TFG, ALB, MGL, DF, and CJP belong to Consejo Nacional de Investigaciones Científicas (CONICET). SS and GC belong to Consejo de Investigación en Salud del Gobierno de la Ciudad Autonóma de Bs. As. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.