Expression of cholesterol sulfotransferase (SULT2B1b) in human platelets.
BACKGROUND
Cholesterol sulfate, the most important sterol sulfate in the human circulation, has emerged as a multifaceted molecule. Among its many demonstrated regulatory actions is its ability to influence blood clotting and fibrinolysis. Additionally, cholesterol sulfate is a constituent of human platelets, where it has been shown to support platelet aggregation.


RESULTS
We have documented the presence of the enzyme (SULT2B1b) that sulfonates cholesterol in human platelets and examined the influence of plasma lipoproteins on the expression and activity of this enzyme. SULT2B1b mRNA was detected by reverse transcription-polymerase chain reaction and found to be the only steroid/sterol sulfotransferase expressed in these discoid anucleate particles. Using real-time polymerase chain reaction for quantification, we found that the level of SULT2B1b mRNA in platelets was maintained at 4 degrees C but substantially diminished over a period of 4 hours at 37 degrees C. The loss of SULT2B1b mRNA, however, was markedly reduced in the presence of HDL but not LDL. The stabilizing influence of HDL was attributable specifically to its apolipoprotein (apo) A-I component, whereas apoA-II and apoE were without effect. Importantly, there was a direct correlation between platelet SULT2B1b mRNA and protein levels in the presence or absence of lipoprotein that was reflected in enzymatic activity and cholesterol sulfate production.


CONCLUSIONS
Human platelets selectively express SULT2B1b, the physiological cholesterol sulfotransferase. Furthermore, the stability of SULT2B1b mRNA and protein in platelets maintained at 37 degrees C is subject to regulation by the apoA-I component of HDL.
Yanai
Hidekatsu
H
Section on Steroid Regulation, Endocrinology, and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Md 20892-4510, USA.
Javitt
Norman B
NB
Higashi
Yuko
Y
Fuda
Hirotoshi
H
Strott
Charles A
CA
D001053:Apolipoproteins / Q000502:physiology; D001792:Blood Platelets / Q000201:enzymology*; D015153:Blotting, Western; D002788:Cholesterol Esters / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000097:blood; D008074:Lipoproteins / Q000502:physiology; D012333:RNA, Messenger / Q000097:blood; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015238:Sulfotransferases / Q000096:biosynthesis / Q000097:blood*
D001053:Apolipoproteins; D002788:Cholesterol Esters; D007527:Isoenzymes; D008074:Lipoproteins; D012333:RNA, Messenger; D015238:Sulfotransferases; C043456:cholesterol sulfotransferase; C433248:SULT2B1 protein, human; C028152:alcohol sulfotransferase; C007045:cholesteryl sulfate