Programa de Pós-Graduação em Ciências Biológicas: Bioquímica-Instituto de Ciências Básica da Saúde-Universidade Federal do Rio Grande Sul, Brazil.
Gene. 2013 Sep 15;527(1):109-14. doi: 10.1016/j.gene.2013.06.002. Epub 2013 Jun 15.
Mucopolysaccharidosis I (MPS I) is a congenital disorder caused by the deficiency of α-l-iduronidase (IDUA), with the accumulation of glycosaminoglycans (GAGs) in the CNS. Although GAG toxicity is not fully understood, previous works suggest a GAG-induced alteration in neuronal membrane composition. This study is aimed to evaluate the levels and distribution of gangliosides and cholesterol in different brain regions (cortex, cerebellum, hippocampus and hypothalamus) in a model using IDUA knockout (KO) mice (C57BL/6). Lipids were extracted with chloroform-methanol and then total gangliosides and cholesterol were determined, followed by ganglioside profile analyses. While no changes in cholesterol content were observed, the results showed a tissue dependent ganglioside alteration in KO mice: a total ganglioside increase in cortex and cerebellum, and a selective presence of GM3, GM2 and GD3 gangliosides in the hippocampus and hypothalamus. To elucidate this, we evaluated gene expression of ganglioside synthesis (GM3, GD3 and GM2/GD2 synthases) and degradation of (Neuraminidase1) enzymes in the cerebellum and hippocampus by RT-sq-PCR. The results obtained with KO mice showed a reduced expression of GD3 and GM2/GD2 synthases and Neuraminidase1 in cerebellum; and a decrease in GM2/GD2 synthase and Neuraminidase1 in the hippocampus. These data suggest that the observed ganglioside changes result from a combined effect of GAGs on ganglioside biosynthesis and degradation.
黏多糖贮积症 I 型（MPS I）是一种由α-L-艾杜糖苷酸酶（IDUA）缺乏引起的先天性疾病，其特征是中枢神经系统（CNS）中糖胺聚糖（GAG）的积累。尽管 GAG 毒性尚未完全阐明，但先前的研究表明 GAG 会引起神经元膜成分的改变。本研究旨在评估 IDUA 基因敲除（KO）小鼠（C57BL/6）模型中不同脑区（皮质、小脑、海马和下丘脑）的神经节苷脂和胆固醇水平及其分布。采用氯仿-甲醇提取法提取脂质，然后测定总神经节苷脂和胆固醇含量，接着进行神经节苷脂谱分析。结果显示，KO 小鼠的胆固醇含量没有变化，但组织依赖性神经节苷脂发生了改变：皮质和小脑的总神经节苷脂增加，而海马和下丘脑选择性存在 GM3、GM2 和 GD3 神经节苷脂。为了阐明这一点，我们通过 RT-sqPCR 评估了小脑和海马中神经节苷脂合成（GM3、GD3 和 GM2/GD2 合成酶）和降解（神经氨酸酶 1）基因的表达。KO 小鼠的结果显示，小脑中 GD3 和 GM2/GD2 合成酶以及神经氨酸酶 1 的表达减少；而海马中 GM2/GD2 合成酶和神经氨酸酶 1 的表达减少。这些数据表明，观察到的神经节苷脂变化是 GAG 对神经节苷脂生物合成和降解的综合作用所致。
