STEROL 27-HYDROXYLASE - EXPRESSION IN HUMAN ARTERIAL ENDOTHELIUM

Human endothelium obtained from both the aorta and the pulmonary arter y has been evaluated for the presence of the messenger RNA coding ibr the expression of sterol 27-hydroxylase. Unique oligomers were designe d to detect the mRNA bg reverse transcription followed by the polymera se chain reaction. The amplified product was sequenced and was found t o be identical to the published sequence for nucleotides 491 to 802 of the human sterol 27-hydroxylase cDNA. Northern blot analysis confirme d the presence 27-hydroxylase mRNA in pulmonary artery and aortic endo thelium. As part of these studies, enzymatic activity was assayed in c ultured arterial endothelium using cholesterol as a substrate and isot ope ratio gas-liquid chromatography-mass spectrometry to identify the metabolites, 27-hydroxycholesterol and 3 beta-hydroxy-5-cholestenoic a cid, in the medium. Localization of sterol 27-hydroxylase to vascular endothelium indicates intracellular production oi the biologically act ive metabolite 27-hydroxycholesterol.