Rodriguez-Lafrasse C, Rousson R, Pentchev P G, Louisot P, Vanier M T
Department of Biochemistry, INSERM-CNRS 189, Lyon-Sud Medical School, Oullins, France.
Biochim Biophys Acta. 1994 May 25;1226(2):138-44. doi: 10.1016/0925-4439(94)90021-3.
The 20-fold increase of free sphingoid bases found in liver from a murine model of Niemann-Pick type C (NPC) combined to the NPC-like phenotype induced by addition of sphinganine to normal fibroblast cultures prompted us to investigate the potential involvement of these compounds in the human disease. The contents of sphingosine and sphinganine were measured in liver, spleen, brain and skin fibroblast cultures by a sensitive HPLC method. In liver and spleen from NPC patients, a 6- to 24-fold elevation of sphingosine and sphinganine already prominent at the fetal stage of the disease was observed, while no clear increase could be evidenced in brain tissue. A significant increase, not modulated by the intralysosomal content of free cholesterol, also occurred in skin fibroblast cultures. To investigate the specificity of these findings, other lysosomal storage disorders were studied. A striking accumulation was found in liver and spleen (24- to 36-fold) from patients with Niemann-Pick disease type A and B (sphingomyelinase-deficient forms), and in cerebral cortex of type A Niemann-Pick disease. A significant storage also occurred in Sandhoff disease, while several other sphingolipidoses showed a moderate elevation. In all cases but Sandhoff disease brain, the sphingosine/sphinganine ratio remained unchanged, suggesting that the accumulated free sphingoid bases derived from sphingolipid catabolism. Formation of complexes between sphingosine and the lipid material accumulated in lysosomes might be a general mechanism in lysosomal lipidoses. In NPC, however, an increase of free sphingoid bases disproportionate to the degree of lysosomal storage and a specific involvement of cultured fibroblasts suggested a more complex or combined mechanism.
在尼曼-匹克C型（NPC）小鼠模型的肝脏中发现游离鞘氨醇碱增加了20倍，同时向正常成纤维细胞培养物中添加鞘氨醇会诱导出NPC样表型，这促使我们研究这些化合物在人类疾病中的潜在作用。通过灵敏的高效液相色谱法测定了肝脏、脾脏、大脑和皮肤成纤维细胞培养物中鞘氨醇和鞘氨醇的含量。在NPC患者的肝脏和脾脏中，观察到鞘氨醇和鞘氨醇在疾病胎儿期就已显著升高6至24倍，而在脑组织中未发现明显增加。皮肤成纤维细胞培养物中也出现了显著增加，且不受游离胆固醇溶酶体内含量的调节。为了研究这些发现的特异性，还研究了其他溶酶体贮积症。在A型和B型尼曼-匹克病（鞘磷脂酶缺乏型）患者的肝脏和脾脏中（24至36倍）以及A型尼曼-匹克病的大脑皮质中发现了显著蓄积。在桑德霍夫病中也出现了显著蓄积，而其他几种鞘脂类疾病则表现为中度升高。除桑德霍夫病大脑外，在所有情况下鞘氨醇/鞘氨醇比值均保持不变，这表明积累的游离鞘氨醇碱来源于鞘脂分解代谢。鞘氨醇与溶酶体中积累的脂质物质之间形成复合物可能是溶酶体脂质贮积症的普遍机制。然而，在NPC中，游离鞘氨醇碱的增加与溶酶体贮积程度不成比例，且培养的成纤维细胞有特异性参与，这表明存在更复杂或联合的机制。
