Studies on the pathogenesis and the treatment of GM1-gangliosidosis mice

gm1神经节脂质沉积症是一种由溶酶体β-半乳糖苷酶（β-Gal）缺乏引起的进行性神经系统疾病，临床分为婴儿、青少年和成人三种形式。我们最近产生了β-Gal敲除（KO）小鼠作为gm1神经节脂质沉积症的真实模型。在本研究中，我们对模型小鼠进行了生化分析，发现神经节苷脂GM1和asialoGM1早在1-2周龄时就开始在其大脑中积累。我们还生成了KO小鼠的C57BL/6基因株，并揭示了其在。原杂交种与原杂交种之间的贮藏材料。为了评估使用腺相关病毒（AAV）载体对gm1神经节骨化症小鼠的基因治疗，我们将含有人β-Gal的AAV注射到小鼠大脑中，并证明在一个月内仅在有限区域检测到酶活性。我们将野生型人β-Gal转基因引入β-Gal KO小鼠，以挽救其gm1神经节脂质病表型。我们还在β-Gal KO小鼠中引入了R201C和I51T氨基酸替换的人β-Gal突变基因，这两种基因分别在幼年和成年gm1神经节脂质体中常见。使用三种含有β-肌动蛋白启动子/人β-Gal cDNA的转基因（野生型、R201C或I51T）。将转基因基因与β-Gal KO小鼠进行杂交，得到的3种KO/转基因小鼠缺乏小鼠β-Gal基因，但具有人β-Gal基因（野生型、R201C和I51T）。结果表明，野生型人β-Gal基因可以挽救小鼠gm1神经节脂质病。表达人β- gal突变体的KO/转基因小鼠可能有助于研究gm1神经节脂质病的发病机制和治疗。

GM1-gangliosidosis is a progressive neurological disease caused by a deficiency of lysosomal β-galactosidase(β-Gal) and is classified into three clinical forms : infantile, juvenile and adult. We recently generated β-Gal knockout(KO) mice as an authentic model of GM1-gangliosidosis. In this study, we conducted biochemical analysis of the model mice and demonstrated that the accumulation of gangliosides GM1 and asialoGM1 occurred as early as 1-2 weeks of age in their brains. We also generated the C57BL/6 congenic strain of KO mice and revealed the some differences in. storage materials between original crossbred and congenic strains. To evaluate the gene therapy using adeno-associated virus(AAV) vector for GM1-gangliosisosis mice, we injected AAV containing human β-Gal into the mouse brain and demonstrated the enzyme activities were detected only in a limited area for one month. We introduced the wild-type human β-Gal transgene into β-Gal KO mice in order to rescue their GM1-gangliosidosis phenotypes. We also introduced into β-Gal KO mice the mutant human β-Gal transgenes with R201C and I51T amino acid substitutions, which were common for juvenile and adult GM1-gangliosidoses, respectively. Three types of transgenes containing the β-actin promoter/human β-Gal cDNA (wild-type, R201C or I51T) were used. Transgenics were bred with β-Gal KO mice, and the resulting three types of KO/transgenic mice lacked mouse β-Gal gene but had human β-Gal (wild-type, R201C or I51T) transgene. As expected, the wild-type human β-Gal transgene could rescue the mouse GM1-gangliosidosis. KO/transgenic mice expressing mutant human β-Gals might be useful for the studies of pathogenesis and treatment of GM1-gangliosidosis with residual enzyme activities.