Bifsha P, Landry K, Ashmarina L, Durand S, Seyrantepe V, Trudel S, Quiniou C, Chemtob S, Xu Y, Gravel R A, Sladek R, Pshezhetsky A V
Sainte-Justine Hospital, Department of Pediatrics and Biochemistry, University of Montreal, Montreal, Canada.
Cell Death Differ. 2007 Mar;14(3):511-23. doi: 10.1038/sj.cdd.4402013. Epub 2006 Aug 4.
By comparing mRNA profiles in cultured fibroblasts from patients affected with lysosomal storage diseases, we identified differentially expressed genes common to these conditions. These studies, confirmed by biochemical experiments, demonstrated that lysosomal storage is associated with downregulation of ubiquitin C-terminal hydrolase, UCH-L1 in the cells of eight different lysosomal disorders, as well as in the brain of a mouse model of Sandhoff disease. Induction of lysosomal storage by the cysteine protease inhibitor E-64 also reduced UCH-L1 mRNA, protein level and activity. All cells exhibiting lysosomal storage contained ubiquitinated protein aggregates and showed reduced levels of free ubiquitin and decreased proteasome activity. The caspase-mediated apoptosis in E-64-treated fibroblasts was reversed by transfection with a UCH-L1 plasmid, and increased after downregulation of UCH-L1 by siRNA, suggesting that UCH-L1 deficiency and impairment of the ubiquitin-dependent protein degradation pathway can contribute to the increased cell death observed in many lysosomal storage disorders.
通过比较溶酶体贮积症患者培养的成纤维细胞中的mRNA谱，我们鉴定出了这些病症共有的差异表达基因。这些研究经生化实验证实，表明在八种不同溶酶体疾病的细胞以及桑德霍夫病小鼠模型的大脑中，溶酶体贮积与泛素C末端水解酶UCH-L1的下调有关。半胱氨酸蛋白酶抑制剂E-64诱导溶酶体贮积也降低了UCH-L1 mRNA、蛋白质水平和活性。所有表现出溶酶体贮积的细胞都含有泛素化蛋白聚集体，并且游离泛素水平降低，蛋白酶体活性下降。用UCH-L1质粒转染可逆转E-64处理的成纤维细胞中由半胱天冬酶介导的凋亡，而通过siRNA下调UCH-L1后凋亡增加，这表明UCH-L1缺乏和泛素依赖性蛋白质降解途径受损可能导致在许多溶酶体贮积症中观察到的细胞死亡增加。
