Regulation of human hepatic hydroxysteroid sulfotransferase gene expression by the peroxisome proliferator-activated receptor alpha transcription factor.
Human hydroxysteroid sulfotransferase or (HUMAN)SULT2A1 catalyzes the sulfonation of procarcinogen xenobiotics, hydroxysteroids, and bile acids and plays a dynamic role in hepatic cholesterol homeostasis. The treatment of primary cultured human hepatocytes with a peroxisome proliferator-activated receptor alpha (PPARalpha)-activating concentration of ciprofibrate (10(-) (4) M) increased (HUMAN)SULT2A1 mRNA, immunoreactive protein, and enzymatic activity levels by approximately 2-fold. By contrast, expression of (RAT)SULT2A3, the rat counterpart to (HUMAN)SULT2A1, was induced by treatment of primary hepatocyte cultures with an activator of the pregnane X receptor, but not PPARalpha. In HepG2 cells, transient transfection analyses of luciferase reporter constructs containing upstream regions of the (HUMAN)SULT2A1 gene implicated a candidate peroxisome proliferator response element (PPRE) at nucleotides (nt) -5949 to -5929 relative to the transcription start site. Site-directed mutagenesis and electrophoretic mobility shift assay studies confirmed that this distal PPRE (dPPRE), a direct repeat nuclear receptor motif containing one intervening nt, represented a functional PPRE. Chromatin immunoprecipitation analysis indicated that the (HUMAN)SULT2A1 dPPRE was also a functional element in the context of the human genome. These data support a major role for the PPARalpha transcription factor in the regulation of hepatic (HUMAN)SULT2A1. Results also indicate that important species differences govern the transactivation of SULT2A gene transcription by nuclear receptors.
Fang
Hai-Lin
HL
Institute of Environmental Health Sciences, Wayne State University, 2727 Second Ave., Room 4000, Detroit, MI 48201, USA.
Strom
Stephen C
SC
Cai
Hongbo
H
Falany
Charles N
CN
Kocarek
Thomas A
TA
Runge-Morris
Melissa
M
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002995:Clofibric Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000502:physiology; D058607:Fibric Acids; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008099:Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D047493:PPAR alpha / Q000502:physiology*; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear; D047488:Retinoid X Receptors / Q000502:physiology; D015238:Sulfotransferases / Q000235:genetics*; D014157:Transcription Factors / Q000502:physiology; D015533:Transcriptional Activation; D000099150:Receptor, Farnesoid X-Activated
D002995:Clofibric Acid; D004268:DNA-Binding Proteins; D058607:Fibric Acids; D047493:PPAR alpha; D018160:Receptors, Cytoplasmic and Nuclear; D047488:Retinoid X Receptors; D015238:Sulfotransferases; D014157:Transcription Factors; D000099150:Receptor, Farnesoid X-Activated; C028152:alcohol sulfotransferase; C019304:ciprofibrate