title: Mitochondrial dysfunctions in 7-ketocholesterol-treated 158N oligodendrocytes without or with α-tocopherol: Impacts on the cellular profil of tricarboxylic cycle-associated organic acids, long chain saturated and unsaturated fatty acids, oxysterols, cholesterol and cholesterol precursors.
abstract: In multiple sclerosis (MS) a process of white matter degradation leading to demyelination is observed. Oxidative stress, inflammation, apoptosis, necrosis and/or autophagy result together into a progressive loss of oligodendrocytes. 7-ketocholesterol (7KC), found increased in the cerebrospinal fluid of MS patients, triggers a rupture of RedOx homeostasis associated with mitochondrial dysfunctions, aptoptosis and autophagy (oxiapoptophagy) in cultured murine oligodendrocytes (158N). α-tocopherol is able to mild the alterations induced by 7KC partially restoring the cellular homeostasis. In presence of 7KC, the amount of adherent 158N cells was decreased and oxidative stress was enhanced. An increase of caspase-3 and PARP degradation (evidences of apoptosis), and an increased LC3-II/LC3-I ratio (criterion of autophagy), were detected. These events were associated with a decrease of the mitochondrial membrane potential (ΔΨm) and by a decrease of oxidative phosphorylation revealed by reduced NAD+and ATP. The cellular lactate was higher while pyruvate, citrate, fumarate, succinate (tricarboxylic acid (TCA) cycle intermediates) were significantly reduced in exposed cells, suggesting that an impairment of mitochondrial respiratory functions could lead to an increase of lactate production and to a reduced amount of ATP and acetyl-CoA available for the anabolic pathways. The concentration of sterol precursors lathosterol, lanosterol and desmosterol were significantly reduced together with satured and unsatured long chain fatty acids (C16:0 - C18:0, structural elements of membrane phospholipids). Such reductions were milder with α-tocopherol. It is likely that the cell death induced by 7KC is associated with mitochondrial dysfunctions, including alterations of oxidative phosphorylation, which could result from lipid anabolism dysfunctions, especially on TCA cycle intermediates. A better knowledge of mitochondrial associated dysfunctions triggered by 7KC will contribute to bring new information on the demyelination processes which are linked with oxidative stress and lipid peroxidation, especially in MS.
authors.affiliation: Laboratory of Clinical Chemistry, Hospital of Varese, ASST-Settelaghi, Varese, Italy; Laboratory of Clinical Pathology, Foundation IRCCS Istituto Neurologico Carlo Besta, Milan, Italy. Electronic address: valerioleoni@hotmail.com.
authors.forename: Valerio
authors.initials: V
authors.lastname: Leoni
authors.affiliation: Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nury
authors.affiliation: Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Vejux
authors.affiliation: Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France; Univ. Monastir, Faculty of Medicine, LR12ES05, Lab-NAFS 'Nutrition - Functional Food & Vascular Health', Monastir, & Univ. Sousse, Faculty of Medicine, Sousse, Tunisia.
authors.forename: Amira
authors.initials: A
authors.lastname: Zarrouk
authors.affiliation: Laboratory of Clinical Pathology, Foundation IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Caccia
authors.affiliation: Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France; Univ. Monastir, Faculty of Medicine, LR12ES05, Lab-NAFS 'Nutrition - Functional Food & Vascular Health', Monastir, & Univ. Sousse, Faculty of Medicine, Sousse, Tunisia.
authors.forename: Meryam
authors.initials: M
authors.lastname: Debbabi
authors.affiliation: Department of Neurology, Univ. Hospital/Univ. Bourgogne Franche Comté, Dijon, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Fromont
authors.affiliation: Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France; Univ. Monastir, Faculty of Medicine, LR12ES05, Lab-NAFS 'Nutrition - Functional Food & Vascular Health', Monastir, & Univ. Sousse, Faculty of Medicine, Sousse, Tunisia.
authors.forename: Randa
authors.initials: R
authors.lastname: Sghaier
authors.affiliation: Department of Neurology, Univ. Hospital/Univ. Bourgogne Franche Comté, Dijon, France.
authors.forename: Thibault
authors.initials: T
authors.lastname: Moreau
authors.affiliation: Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France. Electronic address: gerard.lizard@u-bourgogne.fr.
authors.forename: Gérard
authors.initials: G
authors.lastname: Lizard
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002784:Cholesterol / Q000737:chemistry*; D002952:Citric Acid Cycle; D005231:Fatty Acids, Unsaturated / Q000737:chemistry; D005434:Flow Cytometry; D007249:Inflammation; D007653:Ketocholesterols / Q000737:chemistry*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D015227:Lipid Peroxidation; D008055:Lipids / Q000737:chemistry; D013058:Mass Spectrometry; D053078:Membrane Potential, Mitochondrial; D051379:Mice; D008928:Mitochondria / Q000378:metabolism*; D009103:Multiple Sclerosis / Q000378:metabolism; D009243:NAD / Q000737:chemistry; D009836:Oligodendroglia / Q000166:cytology / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D000072376:Oxysterols / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000378:metabolism; D024502:alpha-Tocopherol / Q000737:chemistry*
chemical_list: D005231:Fatty Acids, Unsaturated; D007653:Ketocholesterols; D008055:Lipids; D000072376:Oxysterols; D017382:Reactive Oxygen Species; D009243:NAD; D000255:Adenosine Triphosphate; D002784:Cholesterol; D007770:L-Lactate Dehydrogenase; D024502:alpha-Tocopherol; C003001:7-ketocholesterol
keywords: 158N murine oligodendrocytes; 7-Ketocholesterol; Lipid profile; Mitochondria; α-Tocopherol