title: Biological activities of the LXRα and β agonist, 4β-hydroxycholesterol, and of its isomer, 4α-hydroxycholesterol, on oligodendrocytes: effects on cell growth and viability, oxidative and inflammatory status.
abstract: The biochemical and biological properties of 4β-hydroxycholesterol and of its isomer, 4α-hydroxycholesterol, are not well known. So, we determined the ability of 4α- and 4β-hydroxycholesterol to react with LXRα and LXRβ, and we characterized the activities of these oxysterols on oligodendrocytes which are myelin synthesizing cells. The effects of 4α- and 4β-hydroxycholesterol were studied on 158N murine oligodendrocytes to assess their activities on cell growth and viability, oxidative and inflammatory status. To this end different parameters were used: cell counting with trypan blue; identification of dead cells and cell cycle analysis with propidium iodide; evaluation of mitochondrial depolarization, lysosomal membrane integrity, actin depolimerization, nuclear morphology, and superoxide anion production after staining with JC-1, acridine orange, rhodamine-phalloidin, Hoechst 33342, and dihydroethidium, respectively; evaluation of ultrastructural changes by transmission electron microscopy, and cytokine quantification with a cytometric bead array. Only 4β-hydroxycholesterol is a LXRα and β agonist. No cytotoxic effects were found with 4α-hydroxycholesterol except a slight inhibition of cell growth at elevated concentrations. At high concentrations, 4β-hydroxycholesterol was not only able to inhibit cell growth, but also to induce cell death associated with a loss of mitochondrial transmembrane potential, dysfunctions of lysosomal membrane integrity, and superoxide anion overproduction. These side effects were lower than those observed with 7-ketocholesterol and 25-hydroxycholesterol used as positive controls. On oligodendrocyte murine primary cultures, only lysosomal membrane integrity was slightly affected under treatment with 4α- and 4β-hydroxycholesterol. So, 4α- and 4β-hydroxycholesterol have different biological activities. Their ability to induce cytotoxic effects on oligodendrocytes can be considered as weak comparatively to 7-ketocholesterol and 25-hydroxycholesterol.
authors.affiliation: Université de Bourgogne, Equipe Biochimie du peroxysome, inflammation et métabolisme lipidique EA 7270/INSERM, Faculté des Sciences Gabriel, 6 Boulevard Gabriel, Dijon, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nury
authors.forename: Mohammad
authors.initials: M
authors.lastname: Samadi
authors.forename: Alexis
authors.initials: A
authors.lastname: Varin
authors.forename: Tatiana
authors.initials: T
authors.lastname: Lopez
authors.forename: Amira
authors.initials: A
authors.lastname: Zarrouk
authors.forename: Mohamed
authors.initials: M
authors.lastname: Boumhras
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Riedinger
authors.forename: David
authors.initials: D
authors.lastname: Masson
authors.forename: Anne
authors.initials: A
authors.lastname: Vejux
authors.forename: Gérard
authors.initials: G
authors.lastname: Lizard
mesh_terms: D000199:Actins / Q000737:chemistry; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism; D006888:Hydroxycholesterols / Q000737:chemistry* / Q000494:pharmacology* / Q000633:toxicity; D007249:Inflammation / Q000378:metabolism; D007536:Isomerism; D000071518:Liver X Receptors; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009836:Oligodendroglia / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D057093:Orphan Nuclear Receptors / Q000819:agonists* / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D055503:Protein Multimerization / Q000187:drug effects; D020836:Protein Structure, Quaternary; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000199:Actins; D016207:Cytokines; D006888:Hydroxycholesterols; D000071518:Liver X Receptors; C000605214:Nr1h3 protein, mouse; D057093:Orphan Nuclear Receptors; D017382:Reactive Oxygen Species; C099828:cholest-5-ene-3,4-diol