title: Expression of sterol 27-hydroxylase (CYP27A1) enhances cholesterol efflux.
abstract: Cholesterol efflux from CHOP cells transfected with sterol 27-hydroxylase (CYP27A1) was compared with non-transfected and mock-transfected cells. Transfection caused expression of CYP27A1, formation of 27-hydroxycholesterol, and inhibition of cholesterol biosynthesis. Transfection enhanced cholesterol efflux to apolipoprotein A-I or human plasma by 2-3-fold but did not affect the efflux in the absence of acceptor. The analysis of released sterols revealed that 27-hydroxycholesterol represented only a small proportion of sterols, most of which was non-oxidized cholesterol. Time course and dose dependence studies showed that expression of CYP27A1 in CHOP cells mostly affected the efflux of the "fast" cholesterol pool, and relatively more cholesterol was released with low concentrations of an acceptor. Preincubation of non-transfected cells with exogenous 27-hydroxycholesterol (10(-9) and 10(-7) m) led to the stimulation of cholesterol efflux by 24-60%. Expression of CYP27A1 in CHOP cells did not affect ABCA1 expression and abundance of ABCA1 protein. Thus, introduction of CYP27A1 into cells stimulates cholesterol efflux and therefore may increase protection against atherosclerosis.
authors.affiliation: Wynn Domain, Baker Medical Research Institute, Melbourne, Victoria 8008, Australia.
authors.forename: Genevieve
authors.initials: G
authors.lastname: Escher
authors.forename: Zygmunt
authors.initials: Z
authors.lastname: Krozowski
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Croft
authors.forename: Dmitri
authors.initials: D
authors.lastname: Sviridov
mesh_terms: D000818:Animals; D001692:Biological Transport; D016466:CHO Cells; D053493:Cholestanetriol 26-Monooxygenase; D002784:Cholesterol / Q000378:metabolism; D002855:Chromatography, Thin Layer; D006224:Cricetinae; D017931:DNA Primers; D006801:Humans; D013250:Steroid Hydroxylases / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D002784:Cholesterol; D013250:Steroid Hydroxylases; C506831:CYP27A1 protein, human; D053493:Cholestanetriol 26-Monooxygenase