Identification of a novel sulfonated oxysterol, 5-cholesten-3beta,25-diol 3-sulfonate, in hepatocyte nuclei and mitochondria.
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.
Ren
Shunlin
S
Department of Medicine, Medical College of Virginia at Virginia Commonwealth University, Richmond, 23298, USA.
Hylemon
Phillip
P
Zhang
Zong-Ping
ZP
Rodriguez-Agudo
Daniel
D
Marques
Dalila
D
Li
Xiaobo
X
Zhou
Huiping
H
Gil
Gregorio
G
Pandak
William M
WM
D000818:Animals; D002467:Cell Nucleus / Q000737:chemistry; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism; D002790:Cholesterol 7-alpha-Hydroxylase / Q000096:biosynthesis; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid / Q000379:methods; D022781:Hepatocytes / Q000737:chemistry*; D006801:Humans; D006888:Hydroxycholesterols / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods; D008930:Mitochondria, Liver / Q000737:chemistry; D010750:Phosphoproteins / Q000096:biosynthesis; D051381:Rats; D013463:Sulfuric Acid Esters / Q000032:analysis*; D000098682:Steroidogenic Acute Regulatory Protein
C511951:5-cholesten-3,25-diol 3-sulfonate; D006888:Hydroxycholesterols; D010750:Phosphoproteins; D013463:Sulfuric Acid Esters; D000098682:Steroidogenic Acute Regulatory Protein; D002784:Cholesterol; D002790:Cholesterol 7-alpha-Hydroxylase