Scandroglio Federica, Venkata Jagadish Kummetha, Loberto Nicoletta, Prioni Simona, Schuchman Edward H, Chigorno Vanna, Prinetti Alessandro, Sonnino Sandro
Center of Excellence on Neurodegenerative Diseases, Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milan, Segrate, Italy.
J Neurochem. 2008 Oct;107(2):329-38. doi: 10.1111/j.1471-4159.2008.05591.x. Epub 2008 Sep 18.
The cholesterol, sphingolipid, and glycerophospholipid content of total brain, of detergent-resistant membranes prepared from the total brain, and of cerebellar granule cells differentiated in culture from wild type (WT) and acid sphingomyelinase knockout (ASMKO) were studied. Brains derived from 7-month-old ASMKO animals showed a fivefold higher level of sphingomyelin and a significant increase in ganglioside content, mainly because of monosialogangliosides GM3 and GM2 accumulation, while the cholesterol and glycerophospholipid content was unchanged with respect to WT animals. An increase in sphingomyelin, but not in gangliosides, was also detected in cultured cerebellar granule neurons from ASMKO mice, indicating that ganglioside accumulation is not a direct consequence of the enzyme defect. When a detergent-resistant membrane fraction was prepared from ASMKO brains, we observed that a higher detergent-to-protein ratio was needed than in WT animals. This likely reflects a reduced fluidity in restricted membrane areas because of a higher enrichment in sphingolipids in the case of ASMKO brain.
研究了全脑、从全脑制备的耐去污剂膜以及从野生型（WT）和酸性鞘磷脂酶基因敲除（ASMKO）小鼠培养分化的小脑颗粒细胞中的胆固醇、鞘脂和甘油磷脂含量。来自7个月大的ASMKO动物的大脑显示鞘磷脂水平高出五倍，神经节苷脂含量显著增加，主要是由于单唾液酸神经节苷脂GM3和GM2的积累，而胆固醇和甘油磷脂含量相对于WT动物没有变化。在来自ASMKO小鼠的培养小脑颗粒神经元中也检测到鞘磷脂增加，但神经节苷脂没有增加，这表明神经节苷脂积累不是酶缺陷的直接后果。当从ASMKO大脑制备耐去污剂膜组分时，我们观察到与WT动物相比，需要更高的去污剂与蛋白质比例。这可能反映了在受限膜区域中流动性降低，因为在ASMKO大脑中鞘脂富集程度更高。
