Pituitary specific retinoid-X receptor ligand interactions with thyroid hormone receptor signaling revealed by high throughput reporter and endogenous gene responses

Brenda J. Mengeling, John Furlow

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Disruption of thyroid hormone (TH) signaling can compromise vital processes both during development and in the adult. We previously reported on high-throughput screening experiments for man-made TH disruptors using a stably integrated line of rat pituitary cells, GH3.TRE-Luc, in which a thyroid hormone receptor (TR) response element drives luciferase (Luc) expression. In these experiments, several retinoid/rexinoid compounds activated the reporter. Here we show that all-trans and 13-cis retinoic acid appear to function through the heterodimer partners of TRs, retinoid-X receptors (RXRs), as RXR antagonists abrogated retinoid-induced activation. The retinoids also induced known endogenous TR target genes, showing good correlation with Luc activity. Synthetic RXR-specific agonists significantly activated all tested TR target genes, but interestingly, retinoid/rexinoid activation was more consistent between genes than the extent of T3-induced activation. In contrast, the retinoids neither activated the Luc reporter construct in transient transfection assays in the human hepatocarcinoma cell line HuH7, nor two of the same T3-induced genes examined in pituitary cells. These data demonstrate the suitability and sensitivity of GH3.TRE-Luc cells for screening chemical compound libraries for TH disruption and suggest that the extent of disruption can vary on a cell type and gene-specific bases, including an underappreciated contribution by RXRs.

Original languageEnglish (US)
Pages (from-to)1609-1618
Number of pages10
JournalToxicology in Vitro
Volume29
Issue number7
DOIs
StatePublished - Oct 1 2015

Keywords

  • Endocrine disruption
  • Reporter gene assay
  • Retinoids
  • Rexinoids
  • Thyroid hormone receptors

ASJC Scopus subject areas

  • Toxicology

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