News & Announcements

Stable Isotope-Labeled Sphingolipids as Highly Specific Mass Spectrometry Standards

Article from 2019-06-03

This article was originally published in the June 2019 edition of Matreya’s Newsletter for Glyco/Sphingolipid Research (PDF).

Sphingolipidomics is the determination of the complete sphingolipid profile of a given system and the metabolism of those sphingolipids. It is the sphingolipid subfield of the greater lipidomics discipline and began to appear as a distinct entity around 2005.1,2 There are tens of thousands of possible naturally occurring sphingolipids that vary in their polar head groups, acyl chains, and sphingoid bases. The metabolic pathway of these sphingolipids has been extensively studied to understand and treat diseases related to sphingolipids and to use sphingolipids to correct various diseases. Many sphingolipids are present in only picomole to nanomole amounts, making detection difficult. However, with the incorporation of soft ionization techniques in mass spectrometry, the detection of very small amounts of sphingolipids is possible. Most sphingolipidomic studies use either liquid chromatography-based or shotgun-based mass spectrometry approaches.3 With both of these approaches, internal standards are used to correct for sample extraction efficiency and instrumentation variability. While adding an internal standard for each individual sphingolipid detected with either of these methods would be ideal, this is impractical due to the vast number of possible sphingolipids in a sample. Thus, internal standards for each class of sphingolipid expected to be found in a sample are used.

Appropriate sphingolipidomic internal standards include sphingolipids that are modified on either the oligosaccharide head, ceramide acyl chain, or the sphingosine backbone.4-6 One of the most preferred internal standards for lipidomic studies are stable isotope-labeled standards. These standards can be easily detected by mass spectrometry, while demonstrating nearly identical physical properties compared to natural sphingolipids. This is very important to ensure similar extraction properties between the analytes and the internal standards.3 Most commonly, deuterium or carbon-13 atoms are introduced in the N-acyl chain of the ceramide. The label can also be introduced into the sphingosine tail or oligosaccharide head group, where it is typically more stable. Another useful internal standard is one that has an acyl or sphingosine chain that has been modified to a length not commonly found in nature, usually C17 or C19.7,8

In addition to the internal standards mentioned above, unlabeled standards are utilized for method development and construction of standard curves for accurate quantification of specific metabolites. Methods have been developed to both synthesize these compounds and to extract them from natural sources. Cayman has 40 years of experience working with lipids and offers an extensive selection of both labeled and naturally occurring standards.

Stable Isotope-Labeled Sphingolipids

References

1. Maceyka, M., Milstein, S., Spiegel, S. Sphingosine kinases, sphingosine-1-phosphate and sphingolipidomics. Prostaglandins Other Lipid Mediat. 77(1-4), 15-22 (2005).

2. Merrill, A.H., Jr., Sullards, M.C., Allegood, J.C., et al. Sphingolipidomics: High-throughput, structure-specific, and quantitative analysis of sphingolipids by liquid chromatography tandem mass spectrometry. Methods 36(2), 207-224 (2005).

3. Han, X. and Jiang, X. A review of lipidomic technologies applicable to sphingolipidomics and their relevant applications. Eur. J. Lipid Sci. Technol. 111(1), 39-52 (2009).

4. Huang, J., Khan, A., Au, B.C., et al. Lentivector iterations and pre-clinical scale-up/toxicity testing: Targeting mobilized CD34+ cells for correction of Fabry disease. Mol. Ther. Methods Clin. Dev. 5, 241-258 (2017).

5. Kleinecke, S., Richert, S., de Hoz, L., et al. Peroxisomal dysfunctions cause lysosomal storage and axonal Kv1 channel redistribution in peripheral neuropathy. Elife 6, e23332 (2017).

6. Sadowski, T., Klose, C., Gerl, M.J., et al. Large-scale human skin lipidomics by quantitative, high-throughput shotgun mass spectrometry. Sci. Rep. 7, 43761 (2017).

7. Merrill, A.H., Jr. Sphingolipid and glycosphingolipid metabolic pathways in the era of sphingolipidomics. Chem. Rev. 111(10), 6387-6422 (2011).

8. Lipsky, N.G. and Pagano, R.E. Intracellular translocation of fluorescent sphingolipids in cultured fibroblasts: Endogenously synthesized sphingomyelin and glucocerebroside analogues pass through the Golgi apparatus en route to the plasma membrane. J. Cell Biol. 100(1), 27-34 (1985).

Receive Our News & Literature Directly to Your Inbox!

Log in or register to subscribe to our email list. You will receive emails packed with new products and content that match your research interests. We only email once a week and you can unsubscribe at any time.