Differentiation of pluripotent C3H10T1/2 cells rapidly elevates CYP1B1 through a novel process that overcomes a loss of Ah Receptor

Arch Biochem Biophys. 2005 Jul 15;439(2):139-53. doi: 10.1016/j.abb.2005.04.025.

Abstract

Stimulation of C3H10T1/2 cells by an adipogenic hormonal mixture (IDM) consisting of insulin (I), dexamethasone (D), and methylisobutylxanthine (M) substantially induces cytochrome P450 (CYP) 1B1 expression. This stimulation represents up to 40% of the level produced by maximum activation of the arylhydrocarbon receptor (AhR) with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Dexamethasone and methylisobutylxanthine in combination produced near maximum elevation of CYP1B1 along with a subsequent decline in AhR that paralleled the rise in peroxisome proliferator-activated receptorgamma1 (PPARgamma1). Inhibitors of AhR activity, which block TCDD induction, did not affect this increase of CYP1B1 expression, which was, therefore, independent of AhR activity. These responses were unaffected by inhibition of DNA synthesis, which was required for PPARgamma1 induction and terminal differentiation. Induction of CYP1B1 mRNA was paralleled by increased CYP1B1 promoter-luciferase reporter activity. The initial 0.8kb of promoter region, which was sufficient for 24h near maximum stimulation, did not contain either the key AhR-responsive elements that mediate the TCDD response or CREB and SF1 elements that mediate cAMP stimulation of rat CYP1B1 in steroidogenic cells. This reporter response to IDM stimulation, but not to TCDD, was maintained in AhR-null fibroblasts. CYP1B1 expression, unlike TCDD induction, was stimulated by IDM in only about half the cells. CYP1B1 expression partially overlapped with PPARgamma expression, which was also inversely related in clonal sub-lines. CYP1B1 expression may, therefore, represent an early stage of differentiation that requires factors associated with DNA synthesis to subsequently generate PPARgamma1.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 1-Methyl-3-isobutylxanthine / pharmacology
  • Adipocytes / cytology
  • Adipocytes / drug effects
  • Adipocytes / metabolism
  • Animals
  • Aryl Hydrocarbon Hydroxylases / drug effects
  • Aryl Hydrocarbon Hydroxylases / metabolism*
  • Aryl Hydrocarbon Receptor Nuclear Translocator
  • CCAAT-Enhancer-Binding Protein-alpha / drug effects
  • CCAAT-Enhancer-Binding Protein-alpha / metabolism
  • CCAAT-Enhancer-Binding Protein-beta / drug effects
  • CCAAT-Enhancer-Binding Protein-beta / metabolism
  • Cell Differentiation / drug effects
  • Cell Differentiation / physiology*
  • Cells, Cultured
  • Cyclic AMP Response Element-Binding Protein / drug effects
  • Cyclic AMP Response Element-Binding Protein / metabolism
  • Cytochrome P-450 CYP1B1
  • DNA / biosynthesis
  • DNA / drug effects
  • DNA-Binding Proteins / drug effects
  • DNA-Binding Proteins / metabolism
  • Dexamethasone / pharmacology
  • Drug Synergism
  • Fibroblasts / drug effects
  • Mice
  • PPAR gamma / drug effects
  • PPAR gamma / metabolism
  • Pluripotent Stem Cells / cytology*
  • Pluripotent Stem Cells / drug effects
  • Pluripotent Stem Cells / metabolism*
  • Polychlorinated Dibenzodioxins / pharmacology
  • Promoter Regions, Genetic
  • Receptors, Aryl Hydrocarbon / antagonists & inhibitors
  • Receptors, Aryl Hydrocarbon / drug effects
  • Receptors, Aryl Hydrocarbon / metabolism*
  • Response Elements / drug effects
  • Transcription Factors / drug effects
  • Transcription Factors / metabolism

Substances

  • Arnt protein, mouse
  • CCAAT-Enhancer-Binding Protein-alpha
  • CCAAT-Enhancer-Binding Protein-beta
  • Cyclic AMP Response Element-Binding Protein
  • DNA-Binding Proteins
  • PPAR gamma
  • Polychlorinated Dibenzodioxins
  • Receptors, Aryl Hydrocarbon
  • Transcription Factors
  • Aryl Hydrocarbon Receptor Nuclear Translocator
  • Dexamethasone
  • DNA
  • Aryl Hydrocarbon Hydroxylases
  • Cyp1b1 protein, mouse
  • Cyp1b1 protein, rat
  • Cytochrome P-450 CYP1B1
  • 1-Methyl-3-isobutylxanthine