Hasholt L, Wandall A, Sørensen S A
Institute of Medical Genetics, Panum Institute, Copenhagen, Denmark.
Clin Genet. 1988 May;33(5):360-71. doi: 10.1111/j.1399-0004.1988.tb03463.x.
Endothelial cells are of particular interest for therapeutic strategies in Fabry's disease, because the accumulation of glycosphingolipids in the vascular endothelium as a result of alpha-galactosidase A (alpha-galA) deficiency is responsible for the major clinical manifestations of the disease. Electron microscopical observations of cultured endothelial cells obtained from the umbilical vein of a hemizygous Fabry fetus showed that the glycosphingolipids are deposited as lamellar material in the lysosomes, as has been found previously for cultured fibroblasts and many different tissues. Mannose 6-phosphate (man 6-P)-receptor mediated and Concanavalin A (ConA)-mediated uptake of purified alpha-galA was attempted in the endothelial cells as well as in cultured fibroblasts from the same fetus. Our results on high-uptake alpha-galA indicate that the endothelial cells do not internalize alpha-galA via the man 6-P receptor. Immunofluorescence studies after addition of the receptor antibody to the cells support the theory that they have no or very few man 6-P receptors on the surface. Morphological studies did not show lysosomal changes which could suggest that the enzyme is taken up into the endothelial cells; however, we found reproducible modifications of the lysosomes in Fabry fibroblasts after incubation with high-uptake alpha-galA. Cell-associated alpha-galA activity was found in both cell types, when the enzyme was added to cells preincubated with ConA; but the lectin treatment by itself induced considerable ultrastructural changes in the cytoplasm, which obscured a possible effect by the enzyme.
内皮细胞在法布里病的治疗策略中具有特别的研究意义，因为α - 半乳糖苷酶A（α - galA）缺乏导致糖鞘脂在血管内皮细胞中蓄积，这是该疾病主要临床表现的病因。对一名半合子法布里病胎儿脐静脉获取的培养内皮细胞进行电子显微镜观察发现，糖鞘脂以层状物质的形式沉积在溶酶体中，这与之前在培养的成纤维细胞和许多不同组织中发现的情况一致。我们尝试在该胎儿的内皮细胞以及培养的成纤维细胞中进行甘露糖6 - 磷酸（man 6 - P）受体介导和刀豆球蛋白A（ConA）介导的纯化α - galA摄取。我们关于高摄取α - galA的研究结果表明，内皮细胞不会通过man 6 - P受体内化α - galA。在细胞中加入受体抗体后的免疫荧光研究支持了这一理论，即它们表面不存在或仅有极少的man 6 - P受体。形态学研究未显示出可能提示该酶被摄取进入内皮细胞的溶酶体变化；然而，我们发现用高摄取α - galA孵育后的法布里病成纤维细胞中溶酶体有可重复的改变。当将该酶添加到预先用ConA孵育的细胞中时，在两种细胞类型中均发现了与细胞相关的α - galA活性；但凝集素处理本身会在细胞质中引起相当大的超微结构变化，并掩盖了该酶可能产生的作用。
