The involvement of organelles in cell death is well established especially for endoplasmic reticulum, lysosomes and mitochondria. However, the role of the peroxisome is not well known, though peroxisomal dysfunction favors a rupture of redox equilibrium. To study the role of peroxisomes in cell death, 158 N murine oligodendrocytes were treated with 7-ketocholesterol (7 KC: 25–50 μM, 24 h). The highest concentration is known to induce oxiapoptophagy (OXIdative stress + APOPTOsis + autoPHAGY), whereas the lowest concentration does not induce cell death. In those conditions (with 7 KC: 50 μM) morphological, topographical and functional peroxisome alterations associated with modifications of the cytoplasmic distribution of mitochondria, with mitochondrial dysfunction (loss of transmembrane mitochondrial potential, decreased level of cardiolipins) and oxidative stress were observed: presence of peroxisomes with abnormal sizes and shapes similar to those observed in Zellweger fibroblasts, lower cellular level of ABCD3, used as a marker of peroxisomal mass, measured by flow cytometry, lower mRNA and protein levels (measured by RT-qPCR and western blotting) of ABCD1 and ABCD3 (two ATP-dependent peroxisomal transporters), and of ACOX1 and MFP2 enzymes, and lower mRNA level of DHAPAT, involved in peroxisomal β-oxidation and plasmalogen synthesis, respectively, and increased levels of very long chain fatty acids (VLCFA: C24:0, C24:1, C26:0 and C26:1, quantified by gas chromatography coupled with mass spectrometry) metabolized by peroxisomal β-oxidation. In the presence of 7 KC (25 μM), slight mitochondrial dysfunction and oxidative stress were found, and no induction of apoptosis was detected; however, modifications of the cytoplasmic distribution of mitochondria and clusters of mitochondria were detected. The peroxisomal alterations observed with 7 KC (25 μM) were similar to those with 7 KC (50 μM). In addition, data obtained by transmission electron microcopy and immunofluorescence microscopy by dual staining with antibodies raised against p62, involved in autophagy, and ABCD3, support that 7 KC (25–50 μM) induces pexophagy. 7 KC (25–50 μM)-induced side effects were attenuated by α-tocopherol but not by α-tocotrienol, whereas the anti-oxidant properties of these molecules determined with the FRAP assay were in the same range. These data provide evidences that 7 KC, at concentrations inducing or not cell death, triggers morphological, topographical and functional peroxisomal alterations associated with minor or major mitochondrial changes.

细胞器参与细胞死亡的机制已经很成熟，特别是对于内质网，溶酶体和线粒体而言。然而，尽管过氧化物酶体功能障碍促进了氧化还原平衡的破坏，但过氧化物酶体的作用尚不为人所知。为了研究过氧化物酶体在细胞死亡中的作用，对158 N鼠少突胶质细胞进行了7-酮胆固醇处理（7 KC：25–50μM，24小时）。已知最高浓度可诱导吞噬细胞（氧化应激+细胞凋亡+自噬），而最低浓度则不会诱导细胞死亡。在这些条件下（7 KC：50μM），形态，地形和功能过氧化物酶体的改变与线粒体细胞质分布的改变，线粒体功能障碍（跨膜线粒体电位的丧失，观察到心磷脂水平降低和氧化应激：过氧化物酶体的大小和形状与在Zellweger成纤维细胞中观察到的相似，具有异常的大小和形状，较低的ABCD3细胞水平用作过氧化物酶体质量的标志物，通过流式细胞仪测量，较低的mRNA和蛋白质分别与过氧化物酶体β-氧化和缩醛磷脂合成有关的ABCD1和ABCD3（两个ATP依赖性过氧化物酶体转运体），ACOX1和MFP2酶的水平（通过RT-qPCR和Western印迹法测量）和较低的DHAPAT mRNA水平，通过过氧化物酶体β-氧化代谢的超长链脂肪酸（VLCFA：C24：0，C24：1，C26：0和C26：1，通过气相色谱和质谱法定量）的水平增加。在存在7 KC（25μM）的情况下，发现了轻微的线粒体功能障碍和氧化应激，没有检测到凋亡的诱导。然而，检测到线粒体的细胞质分布和线粒体簇的改变。用7 KC（25μM）观察到的过氧化物酶体改变与使用7 KC（50μM）观察到的相似。此外，通过透射电子显微镜和免疫荧光显微镜对涉及自噬的针对p62的抗体和ABCD3进行双重染色获得的数据支持7 KC（25–50μM）诱发胸膜炎。α-生育酚可减轻7 KC（25–50μM）诱导的副作用，而α-生育三烯酚不会减轻这些副作用，而用FRAP测定法测定的这些分子的抗氧化特性在相同范围内。这些数据提供了证据，表明7 KC在诱导或不诱导细胞死亡的浓度下触发形态学，