Heine Claudia, Tyynelä Jaana, Cooper Jonathan D, Palmer David N, Elleder Milan, Kohlschütter Alfried, Braulke Thomas
Children's Hospital, University of Hamburg, 20246 Hamburg, Germany.
Biochem J. 2003 Dec 1;376(Pt 2):369-76. doi: 10.1042/BJ20030598.
Neuronal ceroid lipofuscinosis type 6 and its sheep model (OCL6) are lysosomal storage disorders caused by mutations in the CLN6 gene product of unknown function. It has been proposed that mitochondrial dysfunction, including defects in mitochondrial protein degradation, organelle enlargement and functional changes in oxidative phosphorylation, may contribute to the disease pathology. To further explore the disease mechanisms underlying CLN6, protein expression was compared between normal and affected tissues. Using two-dimensional electrophoretic separation of proteins, MS and immunoblotting, MnSOD (manganese-dependent superoxide dismutase) was found to be significantly and specifically increased in fibroblasts and brain extracts of both human and sheep affected with CLN6. Both the activity and expression of MnSOD mRNA were enhanced in affected fibroblasts. Confocal fluorescence microscopy and immunohistochemical studies revealed the presence of MnSOD in mitochondria of CLN6 fibroblasts and in CLN6 brain sections within both neurons and hypertrophic astrocytes. These data suggest that oxidative stress and/or the production of pro-inflammatory cytokines are characteristic features of human and sheep CLN6, resulting in elevated expression of MnSOD, which may be important for diagnostic purposes.
6型神经元蜡样脂褐质沉积症及其绵羊模型（OCL6）是由功能未知的CLN6基因产物突变引起的溶酶体贮积病。有人提出，线粒体功能障碍，包括线粒体蛋白质降解缺陷、细胞器肿大和氧化磷酸化功能变化，可能导致疾病病理。为了进一步探究CLN6潜在的疾病机制，对正常组织和患病组织的蛋白质表达进行了比较。通过二维蛋白质电泳分离、质谱分析和免疫印迹法，发现锰超氧化物歧化酶（MnSOD）在患CLN6的人和绵羊的成纤维细胞及脑提取物中显著且特异性增加。患病变异的成纤维细胞中MnSOD的活性和MnSOD mRNA的表达均增强。共聚焦荧光显微镜和免疫组织化学研究显示，在CLN6成纤维细胞的线粒体以及CLN6脑切片的神经元和肥大星形胶质细胞中均存在MnSOD。这些数据表明，氧化应激和/或促炎细胞因子的产生是人和绵羊CLN6的特征，导致MnSOD表达升高，这可能对诊断具有重要意义。
