Expression and functional regulation of the nuclear receptors AHR, PXR, and CAR, and the transcription factor Nrf2 in rat parotid gland

Eur J Oral Sci. 2014 Aug;122(4):259-64. doi: 10.1111/eos.12137.

Abstract

Nuclear receptors and transcription factors regulate the functions of many genes involved in cellular physiology and pathology (e.g. tumorigenesis and autoimmune diseases). The present study was performed to define the expression and the regulation of aryl hydrocarbon receptor (AhR), pregnane X receptor (PXR), constitutive androstane receptor (CAR), and nuclear factor E2-related factor 2 (Nrf2) in the rat parotid gland. Constitutive expression, as well as expression after stimulation with specific inducers for AhR [2,3,7,8-tetrachloro-dibenzylo-p-dioxin (TCDD)], Nrf2(oltipraz), PXR (dexamethasone), and CAR (phenobarbital), was evaluated using the quantitative PCR. Cellular localization of the nuclear receptors and the transcription factor was visualized by immunohistochemical staining. The study revealed constitutive expression of AhR as well as Nrf2, and their induction by TCDD andoltipraz, respectively. Immunohistochemical analysis revealed constitutive, predominantly cytoplasmic, expression of the AhR receptor, especially in interlobular striated duct cells, with nuclear shift upon exposure to TCDD. Inducible expression of Nfr2 was found mainly in the cytoplasm of intralobular striated duct cells. Constitutive expression of PXR and CAR was not found. Bearing in mind the involvement of AhR and Nrf2 in the regulation of many genes, it seems that these factors may play also a role in salivary gland physiology and pathology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / analysis*
  • Basic Helix-Loop-Helix Transcription Factors / drug effects
  • Cell Nucleus / chemistry
  • Cell Nucleus / ultrastructure
  • Constitutive Androstane Receptor
  • Cytoplasm / chemistry
  • Cytoplasm / ultrastructure
  • Dexamethasone / pharmacology
  • Gene Expression Regulation / drug effects
  • Male
  • NF-E2-Related Factor 2 / analysis*
  • NF-E2-Related Factor 2 / drug effects
  • Parotid Gland / chemistry*
  • Parotid Gland / cytology
  • Parotid Gland / drug effects
  • Phenobarbital / pharmacology
  • Polychlorinated Dibenzodioxins / pharmacology
  • Pregnane X Receptor
  • Pyrazines / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Aryl Hydrocarbon / analysis*
  • Receptors, Aryl Hydrocarbon / drug effects
  • Receptors, Cytoplasmic and Nuclear / analysis*
  • Receptors, Cytoplasmic and Nuclear / drug effects
  • Receptors, Steroid / analysis*
  • Receptors, Steroid / drug effects
  • Salivary Ducts / chemistry
  • Salivary Ducts / cytology
  • Thiones
  • Thiophenes

Substances

  • Ahr protein, rat
  • Basic Helix-Loop-Helix Transcription Factors
  • Constitutive Androstane Receptor
  • NF-E2-Related Factor 2
  • Nfe2l2 protein, rat
  • Polychlorinated Dibenzodioxins
  • Pregnane X Receptor
  • Pyrazines
  • Receptors, Aryl Hydrocarbon
  • Receptors, Cytoplasmic and Nuclear
  • Receptors, Steroid
  • Thiones
  • Thiophenes
  • oltipraz
  • Dexamethasone
  • Phenobarbital