title: Transcriptional Regulation of Cytosolic Sulfotransferase 1C2 by Intermediates of the Cholesterol Biosynthetic Pathway in Primary Cultured Rat Hepatocytes.
abstract: Cytosolic sulfotransferase 1C2 (SULT1C2) is expressed in the kidney, stomach, and liver of rats; however, the mechanisms regulating expression of this enzyme are not known. We evaluated transcriptional regulation of SULT1C2 by mevalonate (MVA)-derived intermediates in primary cultured rat hepatocytes using several cholesterol synthesis inhibitors. Blocking production of mevalonate with the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor pravastatin (30 μM), reduced SULT1C2 mRNA content by ∼40% whereas the squalene synthase inhibitor squalestatin (SQ1, 0.1 μM), which causes accumulation of nonsterol isoprenoids, increased mRNA content by 4-fold. Treatment with MVA (10 mM) strongly induced SULT1C2 mRNA by 12-fold, and this effect was blocked by inhibiting squalene epoxidase but not by more distal cholesterol inhibitors, indicating the effects of MVA are mediated by postsqualene metabolites. Using rapid amplification of cDNA ends (RACE), we characterized the 5' end of SULT1C2 mRNA and used this information to generate constructs for promoter analysis. SQ1 and MVA increased reporter activity by ∼1.6- and 3-fold, respectively, from a construct beginning 49 base pairs (bp) upstream from the longest 5'-RACE product (-3140:-49). Sequence deletions from this construct revealed a hepatocyte nuclear factor 1 (HNF1) element (-2558), and mutation of this element reduced basal (75%) and MVA-induced (30%) reporter activity and attenuated promoter activation following overexpression of HNF1α or 1β. However, the effects of SQ1 were localized to a more proximal promoter region (-281:-49). Collectively, our findings demonstrate that cholesterol biosynthetic intermediates influence SULT1C2 expression in rat primary hepatocytes. Further, HNF1 appears to play an important role in mediating basal and MVA-induced SULT1C2 transcription.
authors.affiliation: Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Rondini
authors.affiliation: Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan.
authors.forename: Asmita
authors.initials: A
authors.lastname: Pant
authors.affiliation: Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan t.kocarek@wayne.edu.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kocarek
mesh_terms: D000818:Animals; D000924:Anticholesteremic Agents / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002784:Cholesterol / Q000096:biosynthesis*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D017930:Genes, Reporter; D051537:Hepatocyte Nuclear Factor 1 / Q000235:genetics / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000201:enzymology*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D008297:Male; D008798:Mevalonic Acid / Q000494:pharmacology; D061251:Primary Cell Culture; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D050603:Squalene Monooxygenase / Q000037:antagonists & inhibitors; D015238:Sulfotransferases / Q000096:biosynthesis* / Q000187:drug effects / Q000235:genetics*; D014162:Transfection; D014233:Tricarboxylic Acids / Q000494:pharmacology
chemical_list: D000924:Anticholesteremic Agents; D019086:Bridged Bicyclo Compounds, Heterocyclic; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D012333:RNA, Messenger; D014233:Tricarboxylic Acids; C075117:squalestatin 1; D051537:Hepatocyte Nuclear Factor 1; D002784:Cholesterol; D050603:Squalene Monooxygenase; D015238:Sulfotransferases; C513315:Sult1c2 protein, rat; D008798:Mevalonic Acid