Identification of a novel sulfonated oxysterol, 5-cholesten-3beta,25-diol 3-sulfonate, in hepatocyte nuclei and mitochondria

J Lipid Res. 2006 May;47(5):1081-90. doi: 10.1194/jlr.M600019-JLR200. Epub 2006 Feb 27.


This study reports the discovery of a novel sulfonated oxysterol found at high levels in the mitochondria and nuclei of primary rat hepatocytes after overexpression of the gene encoding steroidogenic acute regulatory protein (StarD1). Forty-eight hours after infection of primary rat hepatocytes with recombinant adenovirus encoding StarD1, rates of bile acid synthesis increased by 4-fold. Concurrently, [(14)C]cholesterol metabolites (oxysterols) were increased dramatically in both the mitochondria and nuclei of StarD1-overexpressing cells, but not in culture medium. A water-soluble [(14)C]oxysterol product was isolated and purified by chemical extraction and reverse-phase HPLC. Enzymatic digestion, HPLC, and tandem mass spectrometry analysis identified the water-soluble oxysterol as 5-cholesten-3beta,25-diol 3-sulfonate. Further experiments detected this cholesterol metabolite in the nuclei of normal human liver tissues. Based upon these observations, we hypothesized a new pathway by which cholesterol is metabolized in the mitochondrion.

Publication types

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

MeSH terms

  • Animals
  • Cell Nucleus / chemistry
  • Cells, Cultured
  • Cholesterol / metabolism
  • Cholesterol 7-alpha-Hydroxylase / biosynthesis
  • Chromatography, High Pressure Liquid
  • Chromatography, Liquid / methods
  • Hepatocytes / chemistry*
  • Humans
  • Hydroxycholesterols / analysis*
  • Mass Spectrometry / methods
  • Mitochondria, Liver / chemistry
  • Phosphoproteins / biosynthesis
  • Rats
  • Sulfuric Acid Esters / analysis*


  • 5-cholesten-3,25-diol 3-sulfonate
  • Hydroxycholesterols
  • Phosphoproteins
  • Sulfuric Acid Esters
  • steroidogenic acute regulatory protein
  • Cholesterol
  • Cholesterol 7-alpha-Hydroxylase