RT Journal Article SR Electronic T1 Transcriptional regulation of cytosolic sulfotransferase (SULT)1C2 by intermediates of the cholesterol biosynthetic pathway in primary cultured rat hepatocytes JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP jpet.115.226365 DO 10.1124/jpet.115.226365 A1 Elizabeth A. Rondini A1 Asmita Pant A1 Thomas A. Kocarek YR 2015 UL http://jpet.aspetjournals.org/content/early/2015/10/01/jpet.115.226365.abstract AB 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 non-sterol 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 post-squalene 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 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.