Source:natural bovine buttermilk
糖鞘脂广泛分布于动植物组织中。糖鞘脂由结合有糖苷键的神经酰胺组成，神经酰胺与单糖或寡糖结合。乳糖神经酰胺是许多其他糖脂的前体，同时也是第二信使和蛋白质受体，是一种非常重要的有机分子。许多细胞过程依赖于乳糖神经酰胺，因为它是中性寡糖神经酰胺、硫酸酯和神经节苷脂的底物，它们都有自己的重要功能。它也有助于稳定脂质膜，激活受体分子，作为某些细菌和毒素的受体。在动物中，它主要在上皮细胞和神经细胞中发现，它在中性粒细胞和巨噬细胞上表达，并与毒素和细菌结合，然后被吞噬和消除。它作为第二信使的作用已被发现是至关重要的，其过程中的功能失调可导致癌症和炎症，因为它对中性粒细胞活性和激活抗炎反应至关重要。1因此，正在研究它在癌症治疗和其他疾病治疗中的应用。乳糖神经酰胺第二信使功能的其他例子是肿瘤坏死因子α和血小板衍生生长因子。
Lactosylceramide is the precursor of many other glycosphingolipids and also functions as a second messenger and protein receptor, making it a very important organic molecule. Many cellular processes are dependent on lactosylceramide since it is the substrate for neutral oligoglycosylceramides, sulfatides and gangliosides, all of which have their own vital functions. Lactosylceramide also helps to stabilize the lipid membrane, activate receptor molecules and acts as a receptor for certain bacteria and toxins. In animals, where it is found mostly in epithelial and neuronal cells, it is expressed on neutrophils and macrophages where it binds to toxins and bacteria, which are then engulfed and eliminated. Its role as a second messenger has been found to be vital and dysfunctions in its processes can lead to cancer and inflammation since it is critical to neutrophil activity and in activating anti-inflammatory responses.1 Therefore, it is being studied for its use in cancer therapies and as a therapy for other diseases. Other examples of lactosylceramide second messenger functions are tumor necrosis factor alpha and platelet-derived growth factor. A deficiency in the enzyme responsible for hydrolyzing the galactose of lactosylceramide leads to lactosylceramidosis, which is characterized by an accumulation of lactosylceramide that causes a primary neurological disorder.2 Lactosylceramide is also important in the activation of platelet/endothelial cell adhesion molecule-1 which causes adhesion and diapedesis of monocytes/lymphocytes.3
1. R. Pannu et al., Journal of Biological Chemistry, Vol. 280 pp. 13742-13751, 2005
2. G. Dawson, Journal of Lipid Research, Vol. 13 pp. 207-219, 1972
3. N. Gong, Proceedings of the National Academy of Sciences, Vol. 101:17 pp. 6490-6495, 2004
