University Bourgogne Franche-Comté/Inserm , Team 'Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' , Dijon , France.
Laboratory of Biochemistry, Faculty of Medicine , University Sousse , Sousse , Tunisia.
Free Radic Res. 2019 May;53(5):535-561. doi: 10.1080/10715762.2019.1612891.
Mitochondrial dysfunction and oxidative stress are involved in neurodegenerative diseases associated with an enhancement of lipid peroxidation products such as 7β-hydroxycholesterol (7β-OHC). It is, therefore, important to study the ability of 7β-OHC to trigger mitochondrial defects, oxidative stress, metabolic dysfunctions and cell death, which are hallmarks of neurodegeneration, and to identify cytoprotective molecules. The effects of biotin were evaluated on 158N murine oligodendrocytes, which are myelin synthesizing cells, exposed to 7β-OHC (50 µM) with or without biotin (10 and 100 nM) or α-tocopherol (positive control of cytoprotection). The effects of biotin on 7β-OHC activities were determined using different criteria: cell adhesion; plasma membrane integrity; redox status. The impact on mitochondria was characterized by the measurement of transmembrane mitochondrial potential (ΔΨm), reactive oxygen species (ROS) overproduction, mitochondrial mass, quantification of cardiolipins and organic acids. Sterols and fatty acids were also quantified. Cell death (apoptosis, autophagy) was characterized by the enumeration of apoptotic cells, caspase-3 activation, identification of autophagic vesicles, and activation of LC3-I into LC3-II. Biotin attenuates 7β-OHC-induced cytotoxicity: loss of cell adhesion was reduced; antioxidant activities were normalized. ROS overproduction, protein and lipid oxidation products were decreased. Biotin partially restores mitochondrial functions: attenuation of the loss of ΔΨm; reduced levels of mitochondrial O overproduction; normalization of cardiolipins and organic acid levels. Biotin also normalizes cholesterol and fatty acid synthesis, and prevents apoptosis and autophagy (oxiapoptophagy). Our data support that biotin, which prevents oligodendrocytes damages, could be useful in the treatment of neurodegeneration and demyelination.
线粒体功能障碍和氧化应激与神经退行性疾病有关，这些疾病与脂质过氧化产物的增强有关，如 7β-羟胆固醇（7β-OHC）。因此，研究 7β-OHC 引发线粒体缺陷、氧化应激、代谢功能障碍和细胞死亡的能力非常重要，这些都是神经退行性变的标志，并确定细胞保护分子。评估了生物素对 158N 鼠少突胶质细胞（髓鞘合成细胞）的影响，这些细胞暴露于 7β-OHC（50 μM），有或没有生物素（10 和 100 nM）或 α-生育酚（细胞保护的阳性对照）。使用不同的标准来确定生物素对 7β-OHC 活性的影响：细胞黏附；质膜完整性；氧化还原状态。通过测量跨膜线粒体电势（ΔΨm）、活性氧（ROS）的过度产生、线粒体质量、心磷脂和有机酸的定量来描述对线粒体的影响。还定量了固醇和脂肪酸。通过计数凋亡细胞、caspase-3 活化、鉴定自噬小泡和 LC3-I 转化为 LC3-II 来表征细胞死亡（凋亡、自噬）。生物素可减轻 7β-OHC 诱导的细胞毒性：减少细胞黏附丧失；抗氧化活性正常化。ROS 过度产生、蛋白质和脂质氧化产物减少。生物素部分恢复线粒体功能：减轻ΔΨm的丧失；减少线粒体 O 过度产生的水平；心磷脂和有机酸水平正常化。生物素还可使胆固醇和脂肪酸的合成正常化，并防止细胞凋亡和自噬（氧化凋亡）。我们的数据表明，生物素可以防止少突胶质细胞受损，可能对神经退行性疾病和脱髓鞘的治疗有用。
