Ceramides are a group of lipids made up of a fatty acid and sphingosine. Ceramides are component of sphingomyelin lipids, which is one component of lipid bilayer. Therefore, ceramides are highly abundant in cell membranes. In the past, it is assumed that the sole role of ceramides in the cell membrane is acting as the supporting structural elements. However, this assumption turns out to be false. It is shown that ceramides takes part in a series of physiological process in the body.
Ceramides are synthesized by de novo synthesis from serine and palmitoyl-CoA. Acting as precursors for many sphingolipids, ceramides play a crucial role in cell differentiation, cell signaling, proliferation and apoptosis. Catalyzed by the neutral Mg2+-dependent sphingomyelynase, spingomyelin in cell membranes hydrolyze and form ceramides. This is the major synthesis pathway of ceramides. Other minor pathways contributing to ceramide homeostasis include acylation of sphingosine with distinct fatty acyl-CoAs catalyzed by ceramidase and the hydrolysis of ceramide metabolites such as galactosylceramide and glycosylceramide.
Up till now, it’s still unclear how the structure of individual ceramide species is related to their physiological functions. However, it is shown in some reports that specific fatty acids produced in response to some stimuli are components of ceramides. This might gives a clue to the relationship between the structure and function for different ceramide species. It is known that C18 ceramide suppress cell growth, while C16 and C24 ceramide species are associated with cell death. In one in vitro study, it is indicated that by inhibiting Akt, a serine protein kinase involved in insulin action, ceramides suppress glucose uptake. Besides, in insulin resistant animal models, the concentration of ceramides increases in muscle, liver and adipose tissue. The elevation of total ceramide concentrations in human muscle is associated with peripheral insulin resistance. Recently, in obese subjects with type 2 diabetes, it is demonstrated that increased plasma ceramides are related to reduced insulin sensitivity.
Since intracellular involvement of ceramides and their metabolites play a crucial role in lipotoxicity and insulin resistance, it is important to identify the functions of specific ceramides in physiological and pathological process. An accurate, precise and sensitive quantification method for ceramides in plasma and tissue biopsy samples is a necessary for the investigation of the physiological function of specific ceramides. Diacylglycerol (DAG) kinase assay, thin-layer chromatography (TLC) detection, GC-MS and HPLC are the quantification platforms for ceramides. However, these platforms are not only cumbersome and time consuming, it is also difficult for these platforms to simultaneously quantify different specific ceramide species. Creative Proteomics has established sensitive, reliable, and accurate GC-MS method for quantification of ceramides and its metabolites.
Ceramides And Their Metabolites Quantified in This Service
|Ceramides And Their Metabolites Quantified in This Service|
|1||C-14 ceramide (d18:1/14:0)|
|2||C-16 ceramide (d18:1/16:0)|
|3||C-18:0 ceramide (d18:1/16:0)|
|5||C-20 ceramide (d18:1/20:0)|
|6||C-22 ceramide (d18:1/22:0)|
|7||C-24 ceramide (d18:1/24:0)|
With integrated set of separation, characterization, identification and quantification systems featured with excellent robustness & reproducibility, high and ultra-sensitivity, Creative Proteomics provides reliable, rapid and cost-effective ceramides targeted lipidomics services.