Function and Detection of Sphingolipids

Sphingolipids are a class of complex compounds with sphingosine as the backbone. They can be divided into sphingomyelin, glycosphingolipid, and ceramide.

Sphingomyelin is composed of fatty acids, sphingosine and phosphorylcholine. It is found in natural foods, mainly located on cell membranes, lipoproteins and other lipid-rich tissue structures. It is very important for maintaining the cell membrane structure, especially the micro-control function of the cell membrane. It can regulate the activities of growth factor receptors and supercellular matrix proteins, and provide binding sites for some microorganisms, microbial toxins, and viruses.

Glycosphingolipids are composed of fatty acids, sphingosine and sugar groups. As one of the components of the plasma membrane of eukaryotic cells, it not only maintains the basic structure of cells, but also plays an important role in cell adhesion, growth, differentiation, proliferation, signal transduction and other basic cell activities.

Ceramide is a special form of sphingomyelin containing hydrogen instead of phosphorylcholine. It is a synthetic precursor of complex sphingolipids, which is formed by the covalent bonding of long-chain sphingosine to fatty acids through amide bonds, playing a broad and important role in the injury process.

Sphingolipids are commonly found in the cell membranes, organelle membranes, apolipoproteins and lipid-rich organs of various animal and plant cells.

Sphingolipids are important in the formation of lipid rafts and in maintaining their stability. Lipid rafts are micro-regions rich in sphingolipids and cholesterol separated in the cross-section of the lipid bilayer. The affinity of cholesterol and specific sphingolipids determines or partially determines the formation of lipid rafts. Researchers increasingly believe that lipid rafts on the plasma membrane are platforms for the distribution of signal transduction molecules such as receptors and kinases. Some of the signaling functions of ceramide are related to its location in lipid rafts, and the sphingomyelinase reaction to generate ceramide contributes to the formation of lipid rafts.

Lipid rafts are composed of different proteins with different structures and functions. The environment of lipid rafts is conducive to protein metamorphosis and the formation of effective conformations, which allows them to perform a variety of functions, such as participating in signal transduction, in cellular protein function, and in the in vivo circulation of cholesterol and sphingolipids. The physiological function of lipid rafts is multidirectional, and if its normal physiological processes are altered, it can lead to a variety of diseases.

Sphingolipids are involved in intracellular signal transduction and apoptosis, especially ceramide, sphingosine-1-phosphate (S1P), sphingosine and glycosphingolipids. Ceramide and S1P are the most studied bioactive sphingolipids, and they usually have opposite biological effects. Ceramide inhibits cell proliferation and promotes apoptosis, while S1P stimulates cell growth and inhibits apoptosis. Sphingosine can induce apoptosis of a variety of cells, and has a regulatory effect on a variety of intracellular target substances that can regulate cell proliferation or apoptosis. Glycosphingolipids regulate cell growth and differentiation, participate in cellular recognition and interaction, and participate in cellular signal transduction and are involved in tumorigenesis, development, differentiation and metastasis by affecting multiple aspects of signal transduction.

The study of the biological role of sphingolipids in diseases such as cancer has become a hot topic, which further reveals that the study of sphingolipids is of great significance for the life and health of mammals and even humans.

Creative Proteomics uses reversed-phase chromatography LC-ESI-MS/MS coupled with mass spectrometry multiple reaction monitoring (MRM) for quantitative studies of sphingolipids.