Palladini G, Finardi G, Bellomo G
Department of Internal Medicine, University of Pavia, Pavia, Italy.
Exp Cell Res. 1996 Feb 25;223(1):83-90. doi: 10.1006/excr.1996.0060.
Among the different targets of the cytodamaging effects of cholesterol oxides in endothelial cells, cytoskeleton is one of the most relevant, due to the large variety of biological events controlled by this subcellular structure. The modifications of the intermediate filament network caused by three cholesterol oxides (cholestane-3beta,5alpha,6beta-triol, CH, 7-keto-cholesterol, KC, and 25-OH-cholesterol, COH) was investigated in the endothelial cell line 73/73 using immunofluorescence and laser scanner confocal microscopy. All three cholesterol oxides promoted a redistribution of vimentin filaments that took place well before cell detachment and the occurrence of any detectable sign of cell death. CH-induced alterations were characterized by the polarization of vimentin to the edges of the cell and a concomitant destruction of its interaction with the nucleus. In KC-treated cells, vimentin filaments appeared cross-linked and formed a sort of circular network ring between the nucleus and the cell periphery. COH promoted the aggregation of vimentin filaments in thick and irregular bundles that delimited apparently empty regions. All these changes occurred independently of gross modifications in microtubule organization, which was generally retained except for the appearance of immunoreactive tubulin spots throughout the cytoplasm. These results indicate that the organization of the intermediate-size filament protein vimentin is markedly affected by cholesterol oxides. The different rearrangements caused by CH, KC, and COH may derive from different pathobiochemical processes triggered by these compounds.
在内皮细胞中，胆固醇氧化物细胞损伤效应的不同靶点中，细胞骨架是最相关的靶点之一，因为这个亚细胞结构控制着各种各样的生物学事件。使用免疫荧光和激光扫描共聚焦显微镜，研究了三种胆固醇氧化物（胆甾烷 - 3β，5α，6β - 三醇，CH；7 - 酮胆固醇，KC；以及25 - 羟基胆固醇，COH）对内皮细胞系73/73中间丝网络的影响。所有三种胆固醇氧化物均促进波形蛋白丝的重新分布，这种重新分布在细胞脱离以及出现任何可检测到的细胞死亡迹象之前就已经发生。CH诱导的改变表现为波形蛋白向细胞边缘极化，并同时破坏其与细胞核的相互作用。在KC处理的细胞中，波形蛋白丝出现交联，并在细胞核和细胞周边之间形成一种环状网络环。COH促进波形蛋白丝聚集成粗大且不规则的束状，这些束状结构界定了明显的空白区域。所有这些变化的发生都与微管组织的总体改变无关，微管组织通常保持不变，只是在整个细胞质中出现了免疫反应性微管蛋白斑点。这些结果表明，中等大小的丝状蛋白波形蛋白的组织受到胆固醇氧化物的显著影响。CH、KC和COH引起的不同重排可能源于这些化合物引发的不同病理生化过程。
