Igdoura S, Morales C, Tranchemontagne J, Potier M
Department of Anatomy and Cell Biology, McGill University, Montréal, Québec, Canada.
Cell Tissue Res. 1994 Dec;278(3):527-34. doi: 10.1007/BF00331370.
The objectives of this study were to analyze morphologically, morphometrically and immunocytochemically the lysosomal compartment of normal fibroblasts and of fibroblasts with neuraminidase deficiency. The immunocytochemical analyses consisted of quantifying the distribution of saposins and beta-galactosidase in the lysosomes of these cells to test the hypothesis that neuraminidase deficiency is associated with an impairment in the transport of these proteins to the lysosomal compartment. To test this idea, cultured skin fibroblasts of patients with or without sialidosis were prepared for electron microscopy and probed with antibodies against lysosomal beta-galactosidase and lysosomal saposins. The lysosomes of the affected cells had an abnormal accumulation of incompletely digested membranes which was associated with a significant lowering in the density of antigenic sites per lysosome. However, due to a significant increase in the number of lysosomes per affected cell, the total number of antigenic sites in control and neuraminidase deficient cells was similar. This presumably compensatory effect indicates that although the rate of production of beta-galactosidase and saposins remains unchanged, the transport of these molecules to the lysosomes is somehow affected. Our data also indicate that in the fibroblasts, lysosomes require a normal concentration of the three enzymes to maintain neuraminidase activity and sphingolipid degradation.
本研究的目的是对正常成纤维细胞和神经氨酸酶缺乏的成纤维细胞的溶酶体区室进行形态学、形态计量学和免疫细胞化学分析。免疫细胞化学分析包括定量这些细胞溶酶体中鞘脂激活蛋白和β-半乳糖苷酶的分布，以检验神经氨酸酶缺乏与这些蛋白质向溶酶体区室转运受损有关这一假设。为验证这一观点，对患有或未患涎酸沉积症患者的培养皮肤成纤维细胞进行电子显微镜制备，并用抗溶酶体β-半乳糖苷酶和溶酶体鞘脂激活蛋白的抗体进行检测。受影响细胞的溶酶体有未完全消化膜的异常积聚，这与每个溶酶体抗原位点密度的显著降低有关。然而，由于每个受影响细胞中溶酶体数量的显著增加，对照细胞和神经氨酸酶缺乏细胞中抗原位点的总数相似。这种推测的补偿作用表明，尽管β-半乳糖苷酶和鞘脂激活蛋白的产生速率保持不变，但这些分子向溶酶体的转运受到了某种影响。我们的数据还表明，在成纤维细胞中，溶酶体需要正常浓度的这三种酶来维持神经氨酸酶活性和鞘脂降解。
