Meng Xing-Li, Day Taniqua S, McNeill Nathan, Ashcraft Paula, Frischmuth Thomas, Cheng Seng H, Liu Zhi-Ping, Shen Jin-Song, Schiffmann Raphael
Institute of Metabolic Disease, Baylor Research Institute, 3812 Elm Street, Dallas, TX, 75226, USA.
Greenovation Biotech GmbH, Freiburg, Germany.
J Inherit Metab Dis. 2016 May;39(3):447-455. doi: 10.1007/s10545-016-9920-6. Epub 2016 Mar 10.
Fabry disease is caused by deficient activity of α-galactosidase A and subsequent intracellular accumulation of glycosphingolipids, mainly globotriaosylceramide (Gb3). Vascular endothelial cells may play important roles in disease pathogenesis, and are one of the main target cell types in therapeutic interventions. In this study, we generated immortalized aortic endothelial cell lines from a mouse model of Fabry disease. These cells retained endothelial cell-specific markers and functions. Gb3 expression level in one of these clones (referred to as FMEC2) was highly susceptible to culture media, and appeared to be regulated by glucosylceramide synthase. Results also showed that Gb3 could be upregulated by hydrocortisone. FMEC2 express the mannose 6-phosphate receptor and sortilin but not the mannose receptor. Uptake studies suggested that sortilin plays a role in the binding and internalization of mammalian cell-produced α-galactosidase A. Moss-aGal (a plant-made enzyme) was endocytosed by FMEC2 via a receptor other than the aforementioned receptors. In conclusion, this study suggests that glucosylceramide synthase and hydrocortisone may play important roles in modulating Gb3 levels in Fabry mouse aortic endothelial cells, and that endocytosis of recombinant α-galactosidase A involves a combination of multiple receptors depending on the properties of the enzyme.
法布里病由α-半乳糖苷酶A活性不足以及随后糖鞘脂（主要是Globotriaosylceramide，Gb3）在细胞内蓄积所致。血管内皮细胞可能在疾病发病机制中起重要作用，并且是治疗干预的主要靶细胞类型之一。在本研究中，我们从法布里病小鼠模型中生成了永生化主动脉内皮细胞系。这些细胞保留了内皮细胞特异性标志物和功能。其中一个克隆（称为FMEC2）中的Gb3表达水平对培养基高度敏感，并且似乎受葡萄糖神经酰胺合酶调控。结果还表明，氢化可的松可上调Gb3。FMEC2表达甘露糖6-磷酸受体和sortilin，但不表达甘露糖受体。摄取研究表明，sortilin在哺乳动物细胞产生的α-半乳糖苷酶A的结合和内化中起作用。Moss-aGal（一种植物制造的酶）通过上述受体以外的受体被FMEC2内吞。总之，本研究表明，葡萄糖神经酰胺合酶和氢化可的松可能在调节法布里病小鼠主动脉内皮细胞中Gb3水平方面起重要作用，并且重组α-半乳糖苷酶A的内吞作用取决于酶的性质，涉及多种受体的组合。
