title: Enzymatic oxidation of cholesterol: properties and functional effects of cholestenone in cell membranes.
abstract: Bacterial cholesterol oxidase is commonly used as an experimental tool to reduce cellular cholesterol content. That the treatment also generates the poorly degradable metabolite 4-cholesten-3-one (cholestenone) has received less attention. Here, we investigated the membrane partitioning of cholestenone using simulations and cell biological experiments and assessed the functional effects of cholestenone in human cells. Atomistic simulations predicted that cholestenone reduces membrane order, undergoes faster flip-flop and desorbs more readily from membranes than cholesterol. In primary human fibroblasts, cholestenone was released from membranes to physiological extracellular acceptors more avidly than cholesterol, but without acceptors it remained in cells over a day. To address the functional effects of cholestenone, we studied fibroblast migration during wound healing. When cells were either cholesterol oxidase treated or part of cellular cholesterol was exchanged for cholestenone with cyclodextrin, cell migration during 22 h was markedly inhibited. Instead, when a similar fraction of cholesterol was removed using cyclodextrin, cells replenished their cholesterol content in 3 h and migrated similarly to control cells. Thus, cholesterol oxidation produces long-term functional effects in cells and these are in part due to the generated membrane active cholestenone.
authors.affiliation: Institute of Biomedicine, Anatomy, University of Helsinki, Helsinki, Finland.
authors.forename: Maarit
authors.initials: M
authors.lastname: Neuvonen
authors.affiliation: Department of Physics, Tampere University of Technology, Tampere, Finland.
authors.forename: Moutusi
authors.initials: M
authors.lastname: Manna
authors.affiliation: Department of Physics, Tampere University of Technology, Tampere, Finland.
authors.forename: Sini
authors.initials: S
authors.lastname: Mokkila
authors.affiliation: Department of Physics, Tampere University of Technology, Tampere, Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Javanainen
authors.affiliation: Department of Physics, Tampere University of Technology, Tampere, Finland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Rog
authors.affiliation: Department of Chemistry and Biochemistry, Queens College, The City University of New York, Flushing, NY, United States of America.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Chemistry and Biochemistry, Queens College, The City University of New York, Flushing, NY, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Bittman
authors.affiliation: Department of Physics, Tampere University of Technology, Tampere, Finland; MEMPHYS - Center of Biomembrane Physics, University of Southern Denmark, Odense, Denmark.
authors.forename: Ilpo
authors.initials: I
authors.lastname: Vattulainen
authors.affiliation: Institute of Biomedicine, Anatomy, University of Helsinki, Helsinki, Finland; Minerva Foundation Institute for Medical Research, Helsinki, Finland.
authors.forename: Elina
authors.initials: E
authors.lastname: Ikonen
mesh_terms: D000818:Animals; D001419:Bacteria / Q000201:enzymology; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002465:Cell Movement; D002478:Cells, Cultured; D002783:Cholestenones / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism*; D002789:Cholesterol Oxidase / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D051379:Mice; D056004:Molecular Dynamics Simulation; D010084:Oxidation-Reduction
chemical_list: D002783:Cholestenones; C000475:cholest-4-en-3-one; D002784:Cholesterol; D002789:Cholesterol Oxidase